project initialization

backend/tests/contract/test_auth_login.py

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+"""
+Contract test for POST /auth/login endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from django.contrib.auth import get_user_model
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+User = get_user_model()
+
+
+class AuthLoginContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.login_url = '/api/v1/auth/login/'
+
+        # Create test user
+        self.user_data = {
+            'email': 'test@example.com',
+            'password': 'testpass123',
+            'first_name': 'Test',
+            'last_name': 'User'
+        }
+
+    def test_login_success(self):
+        """Test successful login with valid credentials."""
+        response = self.client.post(
+            self.login_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json'
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'access_token' in data
+        assert 'refresh_token' in data
+        assert 'user' in data
+
+        user_data = data['user']
+        assert user_data['email'] == self.user_data['email']
+        assert user_data['first_name'] == self.user_data['first_name']
+        assert user_data['last_name'] == self.user_data['last_name']
+
+    def test_login_invalid_credentials(self):
+        """Test login failure with invalid credentials."""
+        invalid_data = self.user_data.copy()
+        invalid_data['password'] = 'wrongpassword'
+
+        response = self.client.post(
+            self.login_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_login_missing_email(self):
+        """Test login failure with missing email."""
+        incomplete_data = {
+            'password': self.user_data['password']
+        }
+
+        response = self.client.post(
+            self.login_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_login_missing_password(self):
+        """Test login failure with missing password."""
+        incomplete_data = {
+            'email': self.user_data['email']
+        }
+
+        response = self.client.post(
+            self.login_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_login_invalid_content_type(self):
+        """Test login failure with invalid content type."""
+        response = self.client.post(
+            self.login_url,
+            data=json.dumps(self.user_data)
+        )
+
+        assert response.status_code == status.HTTP_415_UNSUPPORTED_MEDIA_TYPE
+
+    def test_login_tenant_specific(self):
+        """Test login with tenant-specific URL."""
+        # This test will check multi-tenant authentication
+        tenant_login_url = '/api/v1/auth/login/'
+
+        response = self.client.post(
+            tenant_login_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json'
+        )
+
+        # Should return tenant-specific information
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            assert 'tenant' in data

backend/tests/contract/test_auth_logout.py

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+"""
+Contract test for POST /auth/logout endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class AuthLogoutContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.logout_url = '/api/v1/auth/logout/'
+
+        # Mock authentication token
+        self.auth_header = {'HTTP_AUTHORIZATION': 'Bearer mock_token'}
+
+    def test_logout_success(self):
+        """Test successful logout with valid token."""
+        response = self.client.post(
+            self.logout_url,
+            **self.auth_header
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'message' in data
+        assert data['message'] == 'Successfully logged out'
+
+    def test_logout_no_token(self):
+        """Test logout failure without authentication token."""
+        response = self.client.post(self.logout_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_logout_invalid_token(self):
+        """Test logout failure with invalid token."""
+        invalid_auth_header = {'HTTP_AUTHORIZATION': 'Bearer invalid_token'}
+
+        response = self.client.post(
+            self.logout_url,
+            **invalid_auth_header
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_logout_expired_token(self):
+        """Test logout failure with expired token."""
+        expired_auth_header = {'HTTP_AUTHORIZATION': 'Bearer expired_token'}
+
+        response = self.client.post(
+            self.logout_url,
+            **expired_auth_header
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_logout_token_blacklisting(self):
+        """Test that logout token is blacklisted."""
+        # This test verifies that the token is added to blacklist
+        response = self.client.post(
+            self.logout_url,
+            **self.auth_header
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            # Token should be blacklisted and cannot be used again
+            second_response = self.client.post(
+                self.logout_url,
+                **self.auth_header
+            )
+            assert second_response.status_code == status.HTTP_401_UNAUTHORIZED

backend/tests/contract/test_auth_refresh.py

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+"""
+Contract test for POST /auth/refresh endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class AuthRefreshContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.refresh_url = '/api/v1/auth/refresh/'
+
+        # Mock refresh token
+        self.refresh_data = {
+            'refresh_token': 'mock_refresh_token'
+        }
+
+    def test_refresh_success(self):
+        """Test successful token refresh with valid refresh token."""
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(self.refresh_data),
+            content_type='application/json'
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'access_token' in data
+        assert 'refresh_token' in data
+
+        # New refresh token should be different (rotation enabled)
+        assert data['refresh_token'] != self.refresh_data['refresh_token']
+
+    def test_refresh_invalid_token(self):
+        """Test refresh failure with invalid refresh token."""
+        invalid_data = {
+            'refresh_token': 'invalid_refresh_token'
+        }
+
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_refresh_missing_token(self):
+        """Test refresh failure with missing refresh token."""
+        incomplete_data = {}
+
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_refresh_blacklisted_token(self):
+        """Test refresh failure with blacklisted token."""
+        blacklisted_data = {
+            'refresh_token': 'blacklisted_refresh_token'
+        }
+
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(blacklisted_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_refresh_expired_token(self):
+        """Test refresh failure with expired refresh token."""
+        expired_data = {
+            'refresh_token': 'expired_refresh_token'
+        }
+
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(expired_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_refresh_tenant_isolation(self):
+        """Test that refresh token respects tenant isolation."""
+        # This test ensures refresh tokens are tenant-specific
+        response = self.client.post(
+            self.refresh_url,
+            data=json.dumps(self.refresh_data),
+            content_type='application/json'
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # Tenant information should be included in token
+            assert 'tenant_id' in data or 'tenant_slug' in data

backend/tests/contract/test_healthcare_appointments_get.py

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+"""
+Contract test for GET /healthcare/appointments endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class HealthcareAppointmentsGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.appointments_url = '/api/v1/healthcare/appointments/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+    def test_get_appointments_success(self):
+        """Test successful retrieval of appointments list."""
+        response = self.client.get(
+            self.appointments_url,
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'appointments' in data
+        assert isinstance(data['appointments'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_appointments_unauthorized(self):
+        """Test appointments list retrieval without authentication."""
+        response = self.client.get(self.appointments_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_appointments_with_pagination(self):
+        """Test appointments list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 20
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 20
+
+    def test_get_appointments_with_search(self):
+        """Test appointments list retrieval with search parameter."""
+        params = {
+            'search': 'ahmad'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should match search criteria
+        for appointment in data['appointments']:
+            search_match = (
+                'ahmad' in appointment['patient_name'].lower() or
+                'ahmad' in appointment['doctor_name'].lower() or
+                'ahmad' in appointment['notes'].lower()
+            )
+            assert search_match
+
+    def test_get_appointments_filter_by_date_range(self):
+        """Test appointments list retrieval filtered by date range."""
+        params = {
+            'start_date': '2024-01-01',
+            'end_date': '2024-01-31'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should be within the date range
+        for appointment in data['appointments']:
+            appointment_date = appointment['appointment_datetime'].split('T')[0]
+            assert '2024-01-01' <= appointment_date <= '2024-01-31'
+
+    def test_get_appointments_filter_by_status(self):
+        """Test appointments list retrieval filtered by status."""
+        params = {
+            'status': 'CONFIRMED'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should have the specified status
+        for appointment in data['appointments']:
+            assert appointment['status'] == 'CONFIRMED'
+
+    def test_get_appointments_filter_by_doctor(self):
+        """Test appointments list retrieval filtered by doctor."""
+        params = {
+            'doctor_id': 'doctor-001'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should be with the specified doctor
+        for appointment in data['appointments']:
+            assert appointment['doctor_id'] == 'doctor-001'
+
+    def test_get_appointments_filter_by_patient(self):
+        """Test appointments list retrieval filtered by patient."""
+        params = {
+            'patient_id': 'patient-001'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should be for the specified patient
+        for appointment in data['appointments']:
+            assert appointment['patient_id'] == 'patient-001'
+
+    def test_get_appointments_data_structure(self):
+        """Test that appointment data structure matches the contract."""
+        response = self.client.get(
+            self.appointments_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['appointments']) > 0:
+            appointment = response.json()['appointments'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'patient_id', 'patient_name', 'doctor_id', 'doctor_name',
+                'appointment_datetime', 'duration', 'status', 'type',
+                'reason', 'notes', 'tenant_id', 'created_at', 'updated_at'
+            ]
+
+            for field in required_fields:
+                assert field in appointment
+
+            # Field types and enums
+            assert isinstance(appointment['id'], str)
+            assert isinstance(appointment['patient_id'], str)
+            assert isinstance(appointment['patient_name'], str)
+            assert isinstance(appointment['doctor_id'], str)
+            assert isinstance(appointment['doctor_name'], str)
+            assert isinstance(appointment['appointment_datetime'], str)
+            assert isinstance(appointment['duration'], int)
+            assert appointment['status'] in ['SCHEDULED', 'CONFIRMED', 'IN_PROGRESS', 'COMPLETED', 'CANCELLED', 'NO_SHOW']
+            assert appointment['type'] in ['CONSULTATION', 'FOLLOW_UP', 'PROCEDURE', 'EMERGENCY', 'CHECKUP']
+
+    def test_get_appointments_with_patient_details(self):
+        """Test that appointment data includes patient details."""
+        response = self.client.get(
+            self.appointments_url,
+            data={'include_patient_details': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['appointments']) > 0:
+            appointment = response.json()['appointments'][0]
+
+            # Should include patient details
+            assert 'patient_details' in appointment
+            patient_details = appointment['patient_details']
+
+            # Patient details should include relevant fields
+            expected_patient_fields = ['ic_number', 'phone', 'email', 'age', 'gender']
+            for field in expected_patient_fields:
+                assert field in patient_details
+
+    def test_get_appointments_with_doctor_details(self):
+        """Test that appointment data includes doctor details."""
+        response = self.client.get(
+            self.appointments_url,
+            data={'include_doctor_details': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['appointments']) > 0:
+            appointment = response.json()['appointments'][0]
+
+            # Should include doctor details
+            assert 'doctor_details' in appointment
+            doctor_details = appointment['doctor_details']
+
+            # Doctor details should include relevant fields
+            expected_doctor_fields = ['specialization', 'license_number', 'department']
+            for field in expected_doctor_fields:
+                assert field in doctor_details
+
+    def test_get_appointments_sorting(self):
+        """Test appointments list retrieval with sorting."""
+        params = {
+            'sort_by': 'appointment_datetime',
+            'sort_order': 'asc'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # Appointments should be sorted by datetime in ascending order
+        appointment_datetimes = [appointment['appointment_datetime'] for appointment in data['appointments']]
+        assert appointment_datetimes == sorted(appointment_datetimes)
+
+    def test_get_appointments_tenant_isolation(self):
+        """Test that appointments are isolated by tenant."""
+        response = self.client.get(
+            self.appointments_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # All returned appointments should belong to the authenticated tenant
+            for appointment in data['appointments']:
+                assert 'tenant_id' in appointment
+                # This will be validated once implementation exists
+
+    def test_get_appointments_upcoming_only(self):
+        """Test appointments list retrieval for upcoming appointments only."""
+        params = {
+            'upcoming_only': 'true'
+        }
+
+        response = self.client.get(
+            self.appointments_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned appointments should be in the future
+        # This will be validated once implementation exists
+        pass
+
+    def test_get_appointments_with_reminders(self):
+        """Test that appointment data includes reminder information."""
+        response = self.client.get(
+            self.appointments_url,
+            data={'include_reminders': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['appointments']) > 0:
+            appointment = response.json()['appointments'][0]
+
+            # Should include reminder information
+            assert 'reminders' in appointment
+            reminders = appointment['reminders']
+
+            # Should be a list
+            assert isinstance(reminders, list)
+
+            if len(reminders) > 0:
+                reminder = reminders[0]
+                expected_reminder_fields = ['type', 'sent_at', 'status']
+                for field in expected_reminder_fields:
+                    assert field in reminder
+
+    def test_get_appointments_with_virtual_info(self):
+        """Test that appointment data includes virtual consultation information."""
+        response = self.client.get(
+            self.appointments_url,
+            data={'include_virtual_info': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['appointments']) > 0:
+            appointment = response.json()['appointments'][0]
+
+            # Should include virtual consultation info if applicable
+            if appointment.get('is_virtual', False):
+                assert 'virtual_consultation' in appointment
+                virtual_info = appointment['virtual_consultation']
+                expected_virtual_fields = ['platform', 'link', 'instructions']
+                for field in expected_virtual_fields:
+                    assert field in virtual_info

backend/tests/contract/test_healthcare_appointments_post.py

@@ -0,0 +1,392 @@
+"""
+Contract test for POST /healthcare/appointments endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class HealthcareAppointmentsPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.appointments_url = '/api/v1/healthcare/appointments/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Valid appointment data
+        self.appointment_data = {
+            'patient_id': 'patient-001',
+            'doctor_id': 'doctor-001',
+            'appointment_datetime': '2024-02-15T14:30:00+08:00',
+            'duration': 30,
+            'type': 'CONSULTATION',
+            'reason': 'Regular checkup for diabetes management',
+            'notes': 'Patient reports occasional dizziness. Need to review medication dosage.',
+            'priority': 'NORMAL',
+            'is_virtual': False,
+            'location': {
+                'room': 'Consultation Room A',
+                'floor': '2nd Floor',
+                'building': 'Main Medical Center'
+            },
+            'reminders': [
+                {
+                    'type': 'SMS',
+                    'time_before': 1440,  # 24 hours
+                    'message': 'Reminder: Your appointment is tomorrow at 2:30 PM'
+                },
+                {
+                    'type': 'EMAIL',
+                    'time_before': 60,  # 1 hour
+                    'message': 'Your appointment is in 1 hour'
+                }
+            ],
+            'follow_up': {
+                'required': True,
+                'interval_days': 30,
+                'notes': 'Follow up to check medication effectiveness'
+            }
+        }
+
+    def test_create_appointment_success(self):
+        """Test successful appointment creation."""
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(self.appointment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['patient_id'] == self.appointment_data['patient_id']
+        assert data['doctor_id'] == self.appointment_data['doctor_id']
+        assert data['appointment_datetime'] == self.appointment_data['appointment_datetime']
+        assert data['duration'] == self.appointment_data['duration']
+        assert data['type'] == self.appointment_data['type']
+        assert data['reason'] == self.appointment_data['reason']
+        assert data['status'] == 'SCHEDULED'  # Default status
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Should have tenant_id from context
+        assert 'tenant_id' in data
+
+        # Should include location information
+        assert 'location' in data
+        assert data['location']['room'] == self.appointment_data['location']['room']
+
+    def test_create_appointment_unauthorized(self):
+        """Test appointment creation without authentication."""
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(self.appointment_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_appointment_missing_required_fields(self):
+        """Test appointment creation with missing required fields."""
+        incomplete_data = self.appointment_data.copy()
+        del incomplete_data['patient_id']
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'patient_id' in data.get('errors', {})
+
+    def test_create_appointment_invalid_datetime(self):
+        """Test appointment creation with invalid datetime format."""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['appointment_datetime'] = 'invalid-datetime-format'
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_appointment_past_datetime(self):
+        """Test appointment creation with past datetime."""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['appointment_datetime'] = '2020-01-01T10:00:00+08:00'  # Past date
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_appointment_invalid_type(self):
+        """Test appointment creation with invalid type."""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['type'] = 'INVALID_TYPE'
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_appointment_negative_duration(self):
+        """Test appointment creation with negative duration."""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['duration'] = -30
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_appointment_doctor_availability_conflict(self):
+        """Test appointment creation with doctor availability conflict."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(self.appointment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same doctor and overlapping time should fail
+            conflicting_data = self.appointment_data.copy()
+            conflicting_data['patient_id'] = 'patient-002'  # Different patient
+            conflicting_data['appointment_datetime'] = '2024-02-15T14:45:00+08:00'  # Overlapping time
+
+            second_response = self.client.post(
+                self.appointments_url,
+                data=json.dumps(conflicting_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+            assert second_response.status_code == status.HTTP_409_CONFLICT
+
+    def test_create_appointment_virtual_consultation(self):
+        """Test appointment creation with virtual consultation."""
+        virtual_data = self.appointment_data.copy()
+        virtual_data['is_virtual'] = True
+        virtual_data['virtual_consultation'] = {
+            'platform': 'ZOOM',
+            'link': 'https://zoom.us/j/123456789',
+            'instructions': 'Please join 5 minutes early. Test your audio and video.',
+            'meeting_id': '123456789',
+            'password': 'health2024'
+        }
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(virtual_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert data['is_virtual'] is True
+            assert 'virtual_consultation' in data
+            virtual_info = data['virtual_consultation']
+            assert virtual_info['platform'] == 'ZOOM'
+
+    def test_create_appointment_emergency(self):
+        """Test emergency appointment creation."""
+        emergency_data = self.appointment_data.copy()
+        emergency_data['type'] = 'EMERGENCY'
+        emergency_data['priority'] = 'URGENT'
+        emergency_data['reason'] = 'Chest pain and shortness of breath'
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(emergency_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert data['type'] == 'EMERGENCY'
+            assert data['priority'] == 'URGENT'
+
+    def test_create_appointment_with_attachments(self):
+        """Test appointment creation with attachments."""
+        attachment_data = self.appointment_data.copy()
+        attachment_data['attachments'] = [
+            {
+                'type': 'MEDICAL_REPORT',
+                'name': 'Blood Test Results.pdf',
+                'url': 'https://storage.example.com/blood-test-123.pdf',
+                'uploaded_at': '2024-02-10T10:00:00Z'
+            },
+            {
+                'type': 'PRESCRIPTION',
+                'name': 'Previous Prescription.jpg',
+                'url': 'https://storage.example.com/prescription-456.jpg',
+                'uploaded_at': '2024-02-08T14:30:00Z'
+            }
+        ]
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(attachment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'attachments' in data
+            assert len(data['attachments']) == 2
+            assert data['attachments'][0]['type'] == 'MEDICAL_REPORT'
+
+    def test_create_appointment_insurance_verification(self):
+        """Test appointment creation with insurance verification."""
+        insurance_data = self.appointment_data.copy()
+        insurance_data['insurance'] = {
+            'provider': 'Malaysia National Insurance',
+            'policy_number': 'MNI-123456789',
+            'verification_required': True,
+            'pre_authorization_code': 'PA-2024-001'
+        }
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(insurance_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'insurance' in data
+            assert data['insurance']['verification_required'] is True
+
+    def test_create_appointment_with_cancellation_policy(self):
+        """Test appointment creation with cancellation policy."""
+        policy_data = self.appointment_data.copy()
+        policy_data['cancellation_policy'] = {
+            'can_cancel_until': '2024-02-14T14:30:00+08:00',  # 24 hours before
+            'cancellation_fee': 50.00,
+            'fee_applies_after': '2024-02-14T14:30:00+08:00'
+        }
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(policy_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'cancellation_policy' in data
+
+    def test_create_appointment_malformed_reminders(self):
+        """Test appointment creation with malformed reminders JSON."""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['reminders'] = 'invalid reminders format'
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_appointment_tenant_isolation(self):
+        """Test that appointment creation respects tenant isolation."""
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(self.appointment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Appointment should be created in the authenticated tenant's context
+            assert 'tenant_id' in data
+            # This will be validated once implementation exists
+
+    def test_create_appointment_scheduling_validation(self):
+        """Test that appointment creation validates business hours and scheduling rules."""
+        # Test with off-hours appointment
+        off_hours_data = self.appointment_data.copy()
+        off_hours_data['appointment_datetime'] = '2024-02-15T22:00:00+08:00'  # 10 PM
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(off_hours_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This should fail if clinic hours are enforced
+        # This will be validated once implementation exists
+        if response.status_code == status.HTTP_400_BAD_REQUEST:
+            pass  # Expected behavior
+        elif response.status_code == status.HTTP_201_CREATED:
+            pass  # Also acceptable if 24/7 appointments are allowed
+
+    def test_create_appointment_with_consent(self):
+        """Test appointment creation with patient consent."""
+        consent_data = self.appointment_data.copy()
+        consent_data['consents'] = [
+            {
+                'type': 'TREATMENT',
+                'given_at': '2024-02-10T10:00:00Z',
+                'expires_at': None,
+                'scope': 'This appointment only'
+            },
+            {
+                'type': 'TELEMEDICINE',
+                'given_at': '2024-02-10T10:00:00Z',
+                'expires_at': '2024-02-15T16:30:00Z',
+                'scope': 'Virtual consultation if needed'
+            }
+        ]
+
+        response = self.client.post(
+            self.appointments_url,
+            data=json.dumps(consent_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'consents' in data
+            assert len(data['consents']) == 2

backend/tests/contract/test_healthcare_patients_get.py

@@ -0,0 +1,326 @@
+"""
+Contract test for GET /healthcare/patients endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class HealthcarePatientsGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.patients_url = '/api/v1/healthcare/patients/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+    def test_get_patients_success(self):
+        """Test successful retrieval of patients list."""
+        response = self.client.get(
+            self.patients_url,
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'patients' in data
+        assert isinstance(data['patients'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_patients_unauthorized(self):
+        """Test patients list retrieval without authentication."""
+        response = self.client.get(self.patients_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_patients_with_pagination(self):
+        """Test patients list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 15
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 15
+
+    def test_get_patients_with_search(self):
+        """Test patients list retrieval with search parameter."""
+        params = {
+            'search': 'tan'
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned patients should match search criteria
+        for patient in data['patients']:
+            search_match = (
+                'tan' in patient['name'].lower() or
+                'tan' in patient['ic_number'].lower() or
+                'tan' in patient['email'].lower()
+            )
+            assert search_match
+
+    def test_get_patients_filter_by_gender(self):
+        """Test patients list retrieval filtered by gender."""
+        params = {
+            'gender': 'FEMALE'
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned patients should have the specified gender
+        for patient in data['patients']:
+            assert patient['gender'] == 'FEMALE'
+
+    def test_get_patients_filter_by_status(self):
+        """Test patients list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned patients should have the specified status
+        for patient in data['patients']:
+            assert patient['status'] == 'ACTIVE'
+
+    def test_get_patients_filter_by_age_range(self):
+        """Test patients list retrieval filtered by age range."""
+        params = {
+            'min_age': 25,
+            'max_age': 65
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned patients should be within the age range
+        for patient in data['patients']:
+            assert 25 <= patient['age'] <= 65
+
+    def test_get_patients_data_structure(self):
+        """Test that patient data structure matches the contract."""
+        response = self.client.get(
+            self.patients_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'ic_number', 'name', 'gender', 'date_of_birth',
+                'age', 'phone', 'email', 'address', 'blood_type',
+                'allergies', 'medications', 'status', 'tenant_id',
+                'created_at', 'updated_at'
+            ]
+
+            for field in required_fields:
+                assert field in patient
+
+            # Field types and enums
+            assert isinstance(patient['id'], str)
+            assert isinstance(patient['ic_number'], str)
+            assert isinstance(patient['name'], str)
+            assert patient['gender'] in ['MALE', 'FEMALE', 'OTHER']
+            assert isinstance(patient['date_of_birth'], str)
+            assert isinstance(patient['age'], int)
+            assert isinstance(patient['phone'], str)
+            assert isinstance(patient['email'], str)
+            assert patient['blood_type'] in ['A+', 'A-', 'B+', 'B-', 'AB+', 'AB-', 'O+', 'O-', 'UNKNOWN']
+            assert patient['status'] in ['ACTIVE', 'INACTIVE', 'DECEASED']
+
+    def test_get_patients_with_medical_history(self):
+        """Test that patient data includes medical history."""
+        response = self.client.get(
+            self.patients_url,
+            data={'include_medical_history': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Should include medical history
+            assert 'medical_history' in patient
+            medical_history = patient['medical_history']
+
+            # Medical history should include relevant fields
+            expected_medical_fields = ['conditions', 'surgeries', 'family_history', 'immunizations']
+            for field in expected_medical_fields:
+                assert field in medical_history
+
+    def test_get_patients_with_emergency_contacts(self):
+        """Test that patient data includes emergency contacts."""
+        response = self.client.get(
+            self.patients_url,
+            data={'include_emergency_contacts': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Should include emergency contacts
+            assert 'emergency_contacts' in patient
+            emergency_contacts = patient['emergency_contacts']
+
+            # Should be a list
+            assert isinstance(emergency_contacts, list)
+
+            if len(emergency_contacts) > 0:
+                contact = emergency_contacts[0]
+                expected_contact_fields = ['name', 'relationship', 'phone', 'email']
+                for field in expected_contact_fields:
+                    assert field in contact
+
+    def test_get_patients_with_insurance_info(self):
+        """Test that patient data includes insurance information."""
+        response = self.client.get(
+            self.patients_url,
+            data={'include_insurance': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Should include insurance information
+            assert 'insurance' in patient
+            insurance = patient['insurance']
+
+            # Insurance should include relevant fields
+            expected_insurance_fields = ['provider', 'policy_number', 'coverage_details', 'expiry_date']
+            for field in expected_insurance_fields:
+                assert field in insurance
+
+    def test_get_patients_sorting(self):
+        """Test patients list retrieval with sorting."""
+        params = {
+            'sort_by': 'name',
+            'sort_order': 'asc'
+        }
+
+        response = self.client.get(
+            self.patients_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # Patients should be sorted by name in ascending order
+        patient_names = [patient['name'] for patient in data['patients']]
+        assert patient_names == sorted(patient_names)
+
+    def test_get_patients_tenant_isolation(self):
+        """Test that patients are isolated by tenant."""
+        response = self.client.get(
+            self.patients_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # All returned patients should belong to the authenticated tenant
+            for patient in data['patients']:
+                assert 'tenant_id' in patient
+                # This will be validated once implementation exists
+
+    def test_get_patients_with_visit_history(self):
+        """Test that patient data includes visit history."""
+        response = self.client.get(
+            self.patients_url,
+            data={'include_visits': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Should include visit history
+            assert 'visit_history' in patient
+            visit_history = patient['visit_history']
+
+            # Should be a list
+            assert isinstance(visit_history, list)
+
+            if len(visit_history) > 0:
+                visit = visit_history[0]
+                expected_visit_fields = ['date', 'doctor_id', 'diagnosis', 'treatment', 'notes']
+                for field in expected_visit_fields:
+                    assert field in visit
+
+    def test_get_patients_data_compliance(self):
+        """Test that patient data complies with healthcare data protection."""
+        response = self.client.get(
+            self.patients_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['patients']) > 0:
+            patient = response.json()['patients'][0]
+
+            # Sensitive medical data should be properly handled
+            # Allergies and medications should be present for healthcare compliance
+            assert 'allergies' in patient
+            assert 'medications' in patient
+
+            # Address should be structured for privacy compliance
+            assert 'address' in patient
+            address = patient['address']
+            expected_address_fields = ['street', 'city', 'state', 'postal_code', 'country']
+            for field in expected_address_fields:
+                assert field in address

backend/tests/contract/test_healthcare_patients_post.py

@@ -0,0 +1,362 @@
+"""
+Contract test for POST /healthcare/patients endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class HealthcarePatientsPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.patients_url = '/api/v1/healthcare/patients/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Valid patient data
+        self.patient_data = {
+            'ic_number': '900101-10-1234',
+            'name': 'Ahmad bin Hassan',
+            'gender': 'MALE',
+            'date_of_birth': '1990-01-01',
+            'phone': '+60123456789',
+            'email': 'ahmad.hassan@example.com',
+            'address': {
+                'street': '123 Jalan Healthcare',
+                'city': 'Kuala Lumpur',
+                'state': 'Wilayah Persekutuan',
+                'postal_code': '50400',
+                'country': 'Malaysia'
+            },
+            'blood_type': 'O+',
+            'allergies': ['Penicillin', 'Peanuts'],
+            'medications': ['Metformin 500mg', 'Lisinopril 10mg'],
+            'emergency_contacts': [
+                {
+                    'name': 'Siti binti Ibrahim',
+                    'relationship': 'Spouse',
+                    'phone': '+60198765432',
+                    'email': 'siti.ibrahim@example.com'
+                }
+            ],
+            'insurance': {
+                'provider': 'Malaysia National Insurance',
+                'policy_number': 'MNI-123456789',
+                'coverage_details': 'Full coverage',
+                'expiry_date': '2024-12-31'
+            },
+            'medical_history': {
+                'conditions': ['Type 2 Diabetes', 'Hypertension'],
+                'surgeries': ['Appendectomy (2015)'],
+                'family_history': ['Diabetes (paternal)', 'Hypertension (maternal)'],
+                'immunizations': ['COVID-19 Vaccine (2023)', 'Flu Vaccine (2023)']
+            }
+        }
+
+    def test_create_patient_success(self):
+        """Test successful patient creation."""
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['ic_number'] == self.patient_data['ic_number']
+        assert data['name'] == self.patient_data['name']
+        assert data['gender'] == self.patient_data['gender']
+        assert data['date_of_birth'] == self.patient_data['date_of_birth']
+        assert data['age'] == 34  # Calculated from DOB
+        assert data['status'] == 'ACTIVE'  # Default status
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Should have tenant_id from context
+        assert 'tenant_id' in data
+
+        # Should include medical information
+        assert data['blood_type'] == self.patient_data['blood_type']
+        assert data['allergies'] == self.patient_data['allergies']
+        assert data['medications'] == self.patient_data['medications']
+
+    def test_create_patient_unauthorized(self):
+        """Test patient creation without authentication."""
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_patient_missing_required_fields(self):
+        """Test patient creation with missing required fields."""
+        incomplete_data = self.patient_data.copy()
+        del incomplete_data['ic_number']
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'ic_number' in data.get('errors', {})
+
+    def test_create_patient_invalid_ic_number(self):
+        """Test patient creation with invalid IC number format."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['ic_number'] = 'invalid-ic-format'
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_invalid_gender(self):
+        """Test patient creation with invalid gender."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['gender'] = 'INVALID_GENDER'
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_invalid_blood_type(self):
+        """Test patient creation with invalid blood type."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['blood_type'] = 'INVALID_BLOOD_TYPE'
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_future_birth_date(self):
+        """Test patient creation with future birth date."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['date_of_birth'] = '2050-01-01'  # Future date
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_duplicate_ic_number(self):
+        """Test patient creation with duplicate IC number."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same IC number should fail
+            second_response = self.client.post(
+                self.patients_url,
+                data=json.dumps(self.patient_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+            assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_with_minimal_data(self):
+        """Test patient creation with minimal required data."""
+        minimal_data = {
+            'ic_number': '950505-05-5678',
+            'name': 'Lee Mei Lin',
+            'gender': 'FEMALE',
+            'date_of_birth': '1995-05-05'
+        }
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(minimal_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert data['ic_number'] == minimal_data['ic_number']
+            assert data['name'] == minimal_data['name']
+            # Optional fields should have default values
+            assert data['blood_type'] == 'UNKNOWN'
+            assert data['allergies'] == []
+
+    def test_create_patient_invalid_email(self):
+        """Test patient creation with invalid email format."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['email'] = 'invalid-email-format'
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_malformed_address(self):
+        """Test patient creation with malformed address JSON."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['address'] = 'invalid address format'
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_missing_address_fields(self):
+        """Test patient creation with missing address fields."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['address'] = {'street': '123 Street'}  # Missing required fields
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_invalid_emergency_contact(self):
+        """Test patient creation with invalid emergency contact."""
+        invalid_data = self.patient_data.copy()
+        invalid_data['emergency_contacts'] = [
+            {
+                'name': 'Emergency Contact',
+                # Missing required relationship and phone
+            }
+        ]
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_patient_age_calculation(self):
+        """Test that age is calculated correctly from date of birth."""
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Age should be calculated based on current date and birth date
+            # This will be validated once implementation exists
+            assert isinstance(data['age'], int)
+            assert data['age'] > 0
+
+    def test_create_patient_tenant_isolation(self):
+        """Test that patient creation respects tenant isolation."""
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Patient should be created in the authenticated tenant's context
+            assert 'tenant_id' in data
+            # This will be validated once implementation exists
+
+    def test_create_patient_data_privacy_compliance(self):
+        """Test that patient creation handles sensitive data according to PDPA."""
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Sensitive medical data should be stored and handled properly
+            assert 'allergies' in data
+            assert 'medications' in data
+            assert 'medical_history' in data
+
+            # IC number should be handled with special care for privacy
+            assert data['ic_number'] == self.patient_data['ic_number']
+
+    def test_create_patient_with_consent_info(self):
+        """Test patient creation with consent information."""
+        consent_data = self.patient_data.copy()
+        consent_data['consents'] = [
+            {
+                'type': 'TREATMENT',
+                'given_at': '2024-01-15T10:00:00Z',
+                'expires_at': '2025-01-15T10:00:00Z',
+                'notes': 'Consent for general treatment'
+            },
+            {
+                'type': 'DATA_SHARING',
+                'given_at': '2024-01-15T10:00:00Z',
+                'expires_at': None,
+                'notes': 'Consent to share data with insurance provider'
+            }
+        ]
+
+        response = self.client.post(
+            self.patients_url,
+            data=json.dumps(consent_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'consents' in data
+            assert len(data['consents']) == 2
+            assert data['consents'][0]['type'] == 'TREATMENT'

backend/tests/contract/test_modules_get.py

@@ -0,0 +1,280 @@
+"""
+Contract test for GET /modules endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class ModulesGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.modules_url = '/api/v1/modules/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Tenant admin authentication header
+        self.tenant_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_admin_token'}
+
+    def test_get_modules_success_admin(self):
+        """Test successful retrieval of modules list by admin."""
+        response = self.client.get(
+            self.modules_url,
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'modules' in data
+        assert isinstance(data['modules'], list)
+
+        # Should return all available modules
+        expected_modules = ['retail', 'healthcare', 'education', 'logistics', 'beauty']
+        returned_modules = [module['key'] for module in data['modules']]
+        for expected_module in expected_modules:
+            assert expected_module in returned_modules
+
+    def test_get_modules_success_tenant_admin(self):
+        """Test successful retrieval of modules list by tenant admin."""
+        response = self.client.get(
+            self.modules_url,
+            **self.tenant_admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'modules' in data
+        assert isinstance(data['modules'], list)
+
+        # Tenant admin should see modules available to their subscription
+        # This will be validated once implementation exists
+
+    def test_get_modules_unauthorized(self):
+        """Test modules list retrieval without authentication."""
+        response = self.client.get(self.modules_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_modules_filter_by_category(self):
+        """Test modules list retrieval filtered by category."""
+        params = {
+            'category': 'core'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned modules should have the specified category
+        for module in data['modules']:
+            assert module['category'] == 'core'
+
+    def test_get_modules_filter_by_status(self):
+        """Test modules list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned modules should have the specified status
+        for module in data['modules']:
+            assert module['status'] == 'ACTIVE'
+
+    def test_get_modules_filter_by_tenant(self):
+        """Test modules list retrieval filtered by tenant subscription."""
+        params = {
+            'tenant_id': 'test-tenant-id',
+            'only_subscribed': 'true'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned modules should be subscribed by the tenant
+        # This will be validated once implementation exists
+
+    def test_get_modules_with_details(self):
+        """Test modules list retrieval with detailed information."""
+        params = {
+            'include_details': 'true'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        if len(data['modules']) > 0:
+            module = data['modules'][0]
+
+            # Should include detailed information
+            assert 'description' in module
+            assert 'features' in module
+            assert 'pricing' in module
+            assert 'requirements' in module
+
+            # Features should be a list
+            assert isinstance(module['features'], list)
+
+            # Pricing should include relevant information
+            pricing = module['pricing']
+            assert 'base_price' in pricing
+            assert 'currency' in pricing
+            assert 'billing_cycle' in pricing
+
+    def test_get_modules_tenant_specific_view(self):
+        """Test that tenant admin sees modules available to their subscription."""
+        response = self.client.get(
+            self.modules_url,
+            **self.tenant_admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # Tenant admin should see which modules are available and which are subscribed
+            # This will be validated once implementation exists
+            pass
+
+    def test_get_modules_data_structure(self):
+        """Test that module data structure matches the contract."""
+        response = self.client.get(
+            self.modules_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['modules']) > 0:
+            module = response.json()['modules'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'key', 'name', 'category', 'status',
+                'version', 'created_at', 'updated_at'
+            ]
+
+            for field in required_fields:
+                assert field in module
+
+            # Field types and enums
+            assert isinstance(module['id'], str)
+            assert isinstance(module['key'], str)
+            assert isinstance(module['name'], str)
+            assert module['category'] in ['core', 'industry', 'integration']
+            assert module['status'] in ['ACTIVE', 'INACTIVE', 'DEPRECATED']
+            assert isinstance(module['version'], str)
+
+    def test_get_modules_with_compatibility_info(self):
+        """Test that module data includes compatibility information."""
+        response = self.client.get(
+            self.modules_url,
+            data={'include_compatibility': 'true'},
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['modules']) > 0:
+            module = response.json()['modules'][0]
+
+            # Should include compatibility information
+            assert 'compatibility' in module
+            compatibility = module['compatibility']
+
+            # Compatibility should include relevant fields
+            expected_compatibility_fields = ['min_platform_version', 'required_modules', 'conflicts']
+            for field in expected_compatibility_fields:
+                assert field in compatibility
+
+    def test_get_modules_with_usage_stats(self):
+        """Test that module data includes usage statistics for admin."""
+        response = self.client.get(
+            self.modules_url,
+            data={'include_stats': 'true'},
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['modules']) > 0:
+            module = response.json()['modules'][0]
+
+            # Should include usage statistics
+            assert 'usage_stats' in module
+            stats = module['usage_stats']
+
+            # Stats should include relevant fields
+            expected_stats_fields = ['active_tenants', 'total_users', 'api_calls_today', 'storage_used']
+            for field in expected_stats_fields:
+                assert field in stats
+
+    def test_get_modules_search(self):
+        """Test modules list retrieval with search functionality."""
+        params = {
+            'search': 'retail'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned modules should match search criteria
+        for module in data['modules']:
+            search_match = (
+                'retail' in module['name'].lower() or
+                'retail' in module['key'].lower() or
+                'retail' in module['description'].lower()
+            )
+            assert search_match
+
+    def test_get_modules_sorting(self):
+        """Test modules list retrieval with sorting."""
+        params = {
+            'sort_by': 'name',
+            'sort_order': 'asc'
+        }
+
+        response = self.client.get(
+            self.modules_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # Modules should be sorted by name in ascending order
+        module_names = [module['name'] for module in data['modules']]
+        assert module_names == sorted(module_names)

backend/tests/contract/test_retail_products_get.py

@@ -0,0 +1,273 @@
+"""
+Contract test for GET /retail/products endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class RetailProductsGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.products_url = '/api/v1/retail/products/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+    def test_get_products_success(self):
+        """Test successful retrieval of products list."""
+        response = self.client.get(
+            self.products_url,
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'products' in data
+        assert isinstance(data['products'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_products_unauthorized(self):
+        """Test products list retrieval without authentication."""
+        response = self.client.get(self.products_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_products_with_pagination(self):
+        """Test products list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 20
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 20
+
+    def test_get_products_with_search(self):
+        """Test products list retrieval with search parameter."""
+        params = {
+            'search': 'laptop'
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned products should match search criteria
+        for product in data['products']:
+            search_match = (
+                'laptop' in product['name'].lower() or
+                'laptop' in product['description'].lower() or
+                'laptop' in product['sku'].lower()
+            )
+            assert search_match
+
+    def test_get_products_filter_by_category(self):
+        """Test products list retrieval filtered by category."""
+        params = {
+            'category': 'ELECTRONICS'
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned products should have the specified category
+        for product in data['products']:
+            assert product['category'] == 'ELECTRONICS'
+
+    def test_get_products_filter_by_status(self):
+        """Test products list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned products should have the specified status
+        for product in data['products']:
+            assert product['status'] == 'ACTIVE'
+
+    def test_get_products_filter_by_price_range(self):
+        """Test products list retrieval filtered by price range."""
+        params = {
+            'min_price': 100,
+            'max_price': 1000
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned products should be within the price range
+        for product in data['products']:
+            assert 100 <= product['price'] <= 1000
+
+    def test_get_products_filter_by_stock(self):
+        """Test products list retrieval filtered by stock availability."""
+        params = {
+            'in_stock': 'true'
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned products should have stock available
+        for product in data['products']:
+            assert product['stock_quantity'] > 0
+
+    def test_get_products_data_structure(self):
+        """Test that product data structure matches the contract."""
+        response = self.client.get(
+            self.products_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['products']) > 0:
+            product = response.json()['products'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'sku', 'name', 'description', 'category',
+                'price', 'cost', 'stock_quantity', 'status',
+                'tenant_id', 'created_at', 'updated_at'
+            ]
+
+            for field in required_fields:
+                assert field in product
+
+            # Field types and enums
+            assert isinstance(product['id'], str)
+            assert isinstance(product['sku'], str)
+            assert isinstance(product['name'], str)
+            assert isinstance(product['description'], str)
+            assert product['category'] in ['ELECTRONICS', 'CLOTHING', 'FOOD', 'BOOKS', 'OTHER']
+            assert isinstance(product['price'], (int, float))
+            assert isinstance(product['cost'], (int, float))
+            assert isinstance(product['stock_quantity'], int)
+            assert product['status'] in ['ACTIVE', 'INACTIVE', 'DISCONTINUED']
+
+    def test_get_products_with_inventory_info(self):
+        """Test that product data includes inventory information."""
+        response = self.client.get(
+            self.products_url,
+            data={'include_inventory': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['products']) > 0:
+            product = response.json()['products'][0]
+
+            # Should include inventory information
+            assert 'inventory' in product
+            inventory = product['inventory']
+
+            # Inventory should include relevant fields
+            expected_inventory_fields = ['location', 'reorder_point', 'supplier', 'last_restocked']
+            for field in expected_inventory_fields:
+                assert field in inventory
+
+    def test_get_products_with_pricing_info(self):
+        """Test that product data includes detailed pricing information."""
+        response = self.client.get(
+            self.products_url,
+            data={'include_pricing': 'true'},
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['products']) > 0:
+            product = response.json()['products'][0]
+
+            # Should include detailed pricing information
+            assert 'pricing' in product
+            pricing = product['pricing']
+
+            # Pricing should include relevant fields
+            expected_pricing_fields = ['base_price', 'tax_rate', 'discount_price', 'currency']
+            for field in expected_pricing_fields:
+                assert field in pricing
+
+    def test_get_products_sorting(self):
+        """Test products list retrieval with sorting."""
+        params = {
+            'sort_by': 'name',
+            'sort_order': 'asc'
+        }
+
+        response = self.client.get(
+            self.products_url,
+            data=params,
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # Products should be sorted by name in ascending order
+        product_names = [product['name'] for product in data['products']]
+        assert product_names == sorted(product_names)
+
+    def test_get_products_tenant_isolation(self):
+        """Test that products are isolated by tenant."""
+        response = self.client.get(
+            self.products_url,
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # All returned products should belong to the authenticated tenant
+            for product in data['products']:
+                assert 'tenant_id' in product
+                # This will be validated once implementation exists

backend/tests/contract/test_retail_products_post.py

@@ -0,0 +1,314 @@
+"""
+Contract test for POST /retail/products endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class RetailProductsPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.products_url = '/api/v1/retail/products/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Valid product data
+        self.product_data = {
+            'sku': 'LPT-001',
+            'name': 'Laptop Pro 15"',
+            'description': 'High-performance laptop for business use',
+            'category': 'ELECTRONICS',
+            'price': 2499.99,
+            'cost': 1800.00,
+            'stock_quantity': 50,
+            'barcode': '1234567890123',
+            'brand': 'TechBrand',
+            'model': 'PRO-15-2024',
+            'weight': 2.5,
+            'dimensions': {
+                'length': 35.5,
+                'width': 25.0,
+                'height': 2.0,
+                'unit': 'cm'
+            },
+            'tax_rate': 6.0,
+            'inventory': {
+                'location': 'Warehouse A',
+                'reorder_point': 10,
+                'supplier': 'TechSupplier Inc.',
+                'lead_time_days': 7
+            },
+            'attributes': {
+                'color': 'Space Gray',
+                'processor': 'Intel i7',
+                'ram': '16GB',
+                'storage': '512GB SSD'
+            }
+        }
+
+    def test_create_product_success(self):
+        """Test successful product creation."""
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(self.product_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['sku'] == self.product_data['sku']
+        assert data['name'] == self.product_data['name']
+        assert data['description'] == self.product_data['description']
+        assert data['category'] == self.product_data['category']
+        assert data['price'] == self.product_data['price']
+        assert data['cost'] == self.product_data['cost']
+        assert data['stock_quantity'] == self.product_data['stock_quantity']
+        assert data['status'] == 'ACTIVE'  # Default status
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Should have tenant_id from context
+        assert 'tenant_id' in data
+
+        # Should include attributes
+        assert 'attributes' in data
+        assert data['attributes']['color'] == self.product_data['attributes']['color']
+
+    def test_create_product_unauthorized(self):
+        """Test product creation without authentication."""
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(self.product_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_product_missing_required_fields(self):
+        """Test product creation with missing required fields."""
+        incomplete_data = self.product_data.copy()
+        del incomplete_data['name']
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'name' in data.get('errors', {})
+
+    def test_create_product_invalid_category(self):
+        """Test product creation with invalid category."""
+        invalid_data = self.product_data.copy()
+        invalid_data['category'] = 'INVALID_CATEGORY'
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_negative_price(self):
+        """Test product creation with negative price."""
+        invalid_data = self.product_data.copy()
+        invalid_data['price'] = -100
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_negative_stock(self):
+        """Test product creation with negative stock quantity."""
+        invalid_data = self.product_data.copy()
+        invalid_data['stock_quantity'] = -10
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_duplicate_sku(self):
+        """Test product creation with duplicate SKU."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.products_url,
+            data=json.dumps(self.product_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same SKU should fail
+            second_response = self.client.post(
+                self.products_url,
+                data=json.dumps(self.product_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+            assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_with_image_urls(self):
+        """Test product creation with image URLs."""
+        image_data = self.product_data.copy()
+        image_data['images'] = [
+            'https://example.com/image1.jpg',
+            'https://example.com/image2.jpg'
+        ]
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(image_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'images' in data
+            assert len(data['images']) == 2
+            assert data['images'][0] == image_data['images'][0]
+
+    def test_create_product_with_variants(self):
+        """Test product creation with variants."""
+        variants_data = self.product_data.copy()
+        variants_data['variants'] = [
+            {
+                'sku': 'LPT-001-BLACK',
+                'name': 'Laptop Pro 15" - Black',
+                'attributes': {'color': 'Black'},
+                'price_adjustment': 0,
+                'stock_quantity': 25
+            },
+            {
+                'sku': 'LPT-001-WHITE',
+                'name': 'Laptop Pro 15" - White',
+                'attributes': {'color': 'White'},
+                'price_adjustment': 50,
+                'stock_quantity': 15
+            }
+        ]
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(variants_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'variants' in data
+            assert len(data['variants']) == 2
+            assert data['variants'][0]['sku'] == 'LPT-001-BLACK'
+
+    def test_create_product_malformed_dimensions(self):
+        """Test product creation with malformed dimensions JSON."""
+        invalid_data = self.product_data.copy()
+        invalid_data['dimensions'] = 'invalid dimensions format'
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_missing_dimension_fields(self):
+        """Test product creation with missing dimension fields."""
+        invalid_data = self.product_data.copy()
+        invalid_data['dimensions'] = {'length': 35.5}  # Missing width, height, unit
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_product_tenant_isolation(self):
+        """Test that product creation respects tenant isolation."""
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(self.product_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Product should be created in the authenticated tenant's context
+            assert 'tenant_id' in data
+            # This will be validated once implementation exists
+
+    def test_create_product_with_tags(self):
+        """Test product creation with tags."""
+        tags_data = self.product_data.copy()
+        tags_data['tags'] = ['laptop', 'business', 'electronics', 'premium']
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(tags_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'tags' in data
+            assert len(data['tags']) == 4
+            assert 'laptop' in data['tags']
+
+    def test_create_product_with_bulk_pricing(self):
+        """Test product creation with bulk pricing tiers."""
+        bulk_data = self.product_data.copy()
+        bulk_data['bulk_pricing'] = [
+            {'min_quantity': 5, 'price': 2399.99},
+            {'min_quantity': 10, 'price': 2299.99},
+            {'min_quantity': 25, 'price': 2199.99}
+        ]
+
+        response = self.client.post(
+            self.products_url,
+            data=json.dumps(bulk_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'bulk_pricing' in data
+            assert len(data['bulk_pricing']) == 3
+            assert data['bulk_pricing'][0]['min_quantity'] == 5

backend/tests/contract/test_retail_sales_post.py

@@ -0,0 +1,388 @@
+"""
+Contract test for POST /retail/sales endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class RetailSalesPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.sales_url = '/api/v1/retail/sales/'
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Valid sale data
+        self.sale_data = {
+            'customer': {
+                'name': 'John Doe',
+                'email': 'john.doe@example.com',
+                'phone': '+60123456789',
+                'address': {
+                    'street': '123 Customer Street',
+                    'city': 'Kuala Lumpur',
+                    'state': 'Wilayah Persekutuan',
+                    'postal_code': '50000',
+                    'country': 'Malaysia'
+                }
+            },
+            'items': [
+                {
+                    'product_id': 'product-001',
+                    'sku': 'LPT-001',
+                    'quantity': 2,
+                    'unit_price': 2499.99,
+                    'discount_percentage': 5.0,
+                    'tax_rate': 6.0
+                },
+                {
+                    'product_id': 'product-002',
+                    'sku': 'MOU-001',
+                    'quantity': 1,
+                    'unit_price': 99.99,
+                    'discount_percentage': 0.0,
+                    'tax_rate': 6.0
+                }
+            ],
+            'payment': {
+                'method': 'CASH',
+                'amount_paid': 5300.00,
+                'reference_number': 'CASH-001'
+            },
+            'discount': {
+                'type': 'percentage',
+                'value': 2.0,
+                'reason': 'Loyalty discount'
+            },
+            'notes': 'Customer requested expedited delivery',
+            'sales_channel': 'IN_STORE',
+            'staff_id': 'staff-001'
+        }
+
+    def test_create_sale_success(self):
+        """Test successful sale creation."""
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(self.sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['status'] == 'COMPLETED'
+        assert 'customer' in data
+        assert 'items' in data
+        assert 'payment' in data
+        assert 'totals' in data
+
+        # Check customer information
+        customer = data['customer']
+        assert customer['name'] == self.sale_data['customer']['name']
+        assert customer['email'] == self.sale_data['customer']['email']
+
+        # Check items
+        items = data['items']
+        assert len(items) == 2
+        assert items[0]['product_id'] == self.sale_data['items'][0]['product_id']
+        assert items[0]['quantity'] == self.sale_data['items'][0]['quantity']
+
+        # Check payment
+        payment = data['payment']
+        assert payment['method'] == self.sale_data['payment']['method']
+        assert payment['amount_paid'] == self.sale_data['payment']['amount_paid']
+
+        # Check totals
+        totals = data['totals']
+        assert 'subtotal' in totals
+        assert 'discount_amount' in totals
+        assert 'tax_amount' in totals
+        assert 'total_amount' in totals
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Should have tenant_id from context
+        assert 'tenant_id' in data
+
+    def test_create_sale_unauthorized(self):
+        """Test sale creation without authentication."""
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(self.sale_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_sale_missing_required_fields(self):
+        """Test sale creation with missing required fields."""
+        incomplete_data = self.sale_data.copy()
+        del incomplete_data['customer']
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'customer' in data.get('errors', {})
+
+    def test_create_sale_empty_items(self):
+        """Test sale creation with empty items list."""
+        invalid_data = self.sale_data.copy()
+        invalid_data['items'] = []
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_sale_invalid_payment_method(self):
+        """Test sale creation with invalid payment method."""
+        invalid_data = self.sale_data.copy()
+        invalid_data['payment']['method'] = 'INVALID_METHOD'
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_sale_insufficient_payment(self):
+        """Test sale creation with insufficient payment amount."""
+        invalid_data = self.sale_data.copy()
+        invalid_data['payment']['amount_paid'] = 100.00  # Much less than total
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_sale_negative_quantity(self):
+        """Test sale creation with negative quantity."""
+        invalid_data = self.sale_data.copy()
+        invalid_data['items'][0]['quantity'] = -1
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_sale_invalid_discount_percentage(self):
+        """Test sale creation with invalid discount percentage."""
+        invalid_data = self.sale_data.copy()
+        invalid_data['items'][0]['discount_percentage'] = 150.0  # Over 100%
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_sale_with_installment(self):
+        """Test sale creation with installment payment."""
+        installment_data = self.sale_data.copy()
+        installment_data['payment']['method'] = 'INSTALLMENT'
+        installment_data['payment']['installment_plan'] = {
+            'down_payment': 1000.00,
+            'number_of_installments': 12,
+            'installment_amount': 358.33,
+            'first_installment_date': '2024-02-01'
+        }
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(installment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert data['status'] == 'COMPLETED'
+            assert 'installment_plan' in data['payment']
+
+    def test_create_sale_with_multiple_payments(self):
+        """Test sale creation with multiple payment methods."""
+        multi_payment_data = self.sale_data.copy()
+        multi_payment_data['payment'] = [
+            {
+                'method': 'CASH',
+                'amount_paid': 2000.00,
+                'reference_number': 'CASH-001'
+            },
+            {
+                'method': 'CARD',
+                'amount_paid': 3300.00,
+                'reference_number': 'CARD-001',
+                'card_last4': '4242'
+            }
+        ]
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(multi_payment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert len(data['payment']) == 2
+            assert data['payment'][0]['method'] == 'CASH'
+
+    def test_create_sale_with_loyalty_points(self):
+        """Test sale creation with loyalty points redemption."""
+        loyalty_data = self.sale_data.copy()
+        loyalty_data['loyalty'] = {
+            'points_used': 1000,
+            'points_value': 100.00,
+            'customer_id': 'customer-001'
+        }
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(loyalty_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'loyalty' in data
+            assert data['loyalty']['points_used'] == 1000
+
+    def test_create_sale_with_delivery_info(self):
+        """Test sale creation with delivery information."""
+        delivery_data = self.sale_data.copy()
+        delivery_data['delivery'] = {
+            'method': 'DELIVERY',
+            'address': self.sale_data['customer']['address'],
+            'scheduled_date': '2024-01-20',
+            'delivery_fee': 50.00,
+            'notes': 'Leave at front door'
+        }
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(delivery_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'delivery' in data
+            assert data['delivery']['method'] == 'DELIVERY'
+
+    def test_create_sale_with_exchange_items(self):
+        """Test sale creation with item exchange."""
+        exchange_data = self.sale_data.copy()
+        exchange_data['exchange'] = {
+            'items': [
+                {
+                    'product_id': 'old-product-001',
+                    'sku': 'OLD-001',
+                    'condition': 'GOOD',
+                    'exchange_value': 500.00
+                }
+            ],
+            'total_exchange_value': 500.00
+        }
+
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(exchange_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'exchange' in data
+            assert len(data['exchange']['items']) == 1
+
+    def test_create_sale_tax_calculation(self):
+        """Test that tax calculation is correct."""
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(self.sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            totals = data['totals']
+
+            # Verify tax calculation (6% GST on subtotal after discounts)
+            # This will be validated once implementation exists
+            assert 'tax_amount' in totals
+            assert totals['tax_amount'] >= 0
+
+    def test_create_sale_tenant_isolation(self):
+        """Test that sale creation respects tenant isolation."""
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(self.sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Sale should be created in the authenticated tenant's context
+            assert 'tenant_id' in data
+            # This will be validated once implementation exists
+
+    def test_create_sale_inventory_validation(self):
+        """Test that sale creation validates inventory availability."""
+        response = self.client.post(
+            self.sales_url,
+            data=json.dumps(self.sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        # This test will ensure that the system checks if sufficient stock is available
+        # The test should pass if implementation exists and validates inventory
+        if response.status_code == status.HTTP_201_CREATED:
+            # Success means inventory was available
+            pass
+        elif response.status_code == status.HTTP_400_BAD_REQUEST:
+            # This could also be valid if inventory validation fails
+            pass

backend/tests/contract/test_subscriptions_get.py

@@ -0,0 +1,224 @@
+"""
+Contract test for GET /subscriptions endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class SubscriptionsGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.subscriptions_url = '/api/v1/subscriptions/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Tenant admin authentication header
+        self.tenant_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_admin_token'}
+
+    def test_get_subscriptions_success_admin(self):
+        """Test successful retrieval of subscriptions list by admin."""
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'subscriptions' in data
+        assert isinstance(data['subscriptions'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_subscriptions_success_tenant_admin(self):
+        """Test successful retrieval of subscriptions list by tenant admin."""
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.tenant_admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'subscriptions' in data
+        assert isinstance(data['subscriptions'], list)
+
+        # Tenant admin should only see subscriptions from their tenant
+        # This will be validated once implementation exists
+
+    def test_get_subscriptions_unauthorized(self):
+        """Test subscriptions list retrieval without authentication."""
+        response = self.client.get(self.subscriptions_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_subscriptions_with_pagination(self):
+        """Test subscriptions list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 10
+        }
+
+        response = self.client.get(
+            self.subscriptions_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 10
+
+    def test_get_subscriptions_filter_by_status(self):
+        """Test subscriptions list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.subscriptions_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned subscriptions should have the specified status
+        for subscription in data['subscriptions']:
+            assert subscription['status'] == 'ACTIVE'
+
+    def test_get_subscriptions_filter_by_plan(self):
+        """Test subscriptions list retrieval filtered by plan."""
+        params = {
+            'plan': 'GROWTH'
+        }
+
+        response = self.client.get(
+            self.subscriptions_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned subscriptions should have the specified plan
+        for subscription in data['subscriptions']:
+            assert subscription['plan'] == 'GROWTH'
+
+    def test_get_subscriptions_filter_by_tenant(self):
+        """Test subscriptions list retrieval filtered by tenant."""
+        params = {
+            'tenant_id': 'test-tenant-id'
+        }
+
+        response = self.client.get(
+            self.subscriptions_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned subscriptions should belong to the specified tenant
+        for subscription in data['subscriptions']:
+            assert subscription['tenant_id'] == 'test-tenant-id'
+
+    def test_get_subscriptions_tenant_isolation(self):
+        """Test that tenant admin can only see subscriptions from their tenant."""
+        # This test verifies tenant isolation for subscription data
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.tenant_admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # For tenant users, all returned subscriptions should belong to their tenant
+            # This will be validated once implementation exists
+            pass
+
+    def test_get_subscriptions_data_structure(self):
+        """Test that subscription data structure matches the contract."""
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['subscriptions']) > 0:
+            subscription = response.json()['subscriptions'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'tenant_id', 'plan', 'status', 'pricing_model',
+                'billing_cycle', 'current_period_start', 'current_period_end',
+                'trial_end', 'created_at', 'updated_at'
+            ]
+
+            for field in required_fields:
+                assert field in subscription
+
+            # Field types and enums
+            assert isinstance(subscription['id'], str)
+            assert isinstance(subscription['tenant_id'], str)
+            assert subscription['plan'] in ['STARTER', 'GROWTH', 'PRO', 'ENTERPRISE']
+            assert subscription['status'] in ['TRIAL', 'ACTIVE', 'PAST_DUE', 'CANCELLED', 'EXPIRED']
+            assert subscription['pricing_model'] in ['SUBSCRIPTION', 'PERPETUAL']
+            assert subscription['billing_cycle'] in ['MONTHLY', 'QUARTERLY', 'YEARLY']
+
+    def test_get_subscriptions_with_usage_data(self):
+        """Test that subscription data includes usage information."""
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['subscriptions']) > 0:
+            subscription = response.json()['subscriptions'][0]
+
+            # Should include usage metrics
+            assert 'usage' in subscription
+            usage = subscription['usage']
+
+            # Usage should include relevant metrics
+            expected_usage_fields = ['users_count', 'storage_used', 'api_calls']
+            for field in expected_usage_fields:
+                assert field in usage
+
+    def test_get_subscriptions_with_billing_info(self):
+        """Test that subscription data includes billing information."""
+        response = self.client.get(
+            self.subscriptions_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['subscriptions']) > 0:
+            subscription = response.json()['subscriptions'][0]
+
+            # Should include billing information
+            assert 'billing' in subscription
+            billing = subscription['billing']
+
+            # Billing should include relevant fields
+            expected_billing_fields = ['next_billing_date', 'amount', 'currency', 'payment_method']
+            for field in expected_billing_fields:
+                assert field in billing

backend/tests/contract/test_subscriptions_post.py

@@ -0,0 +1,264 @@
+"""
+Contract test for POST /subscriptions endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class SubscriptionsPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.subscriptions_url = '/api/v1/subscriptions/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Tenant admin authentication header
+        self.tenant_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_admin_token'}
+
+        # Valid subscription data
+        self.subscription_data = {
+            'tenant_id': 'test-tenant-id',
+            'plan': 'GROWTH',
+            'pricing_model': 'SUBSCRIPTION',
+            'billing_cycle': 'MONTHLY',
+            'payment_method': {
+                'type': 'CARD',
+                'card_last4': '4242',
+                'expiry_month': 12,
+                'expiry_year': 2025,
+                'brand': 'visa'
+            },
+            'modules': ['retail', 'inventory'],
+            'trial_days': 14,
+            'notes': 'Subscription for retail business'
+        }
+
+    def test_create_subscription_success_admin(self):
+        """Test successful subscription creation by admin."""
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['tenant_id'] == self.subscription_data['tenant_id']
+        assert data['plan'] == self.subscription_data['plan']
+        assert data['pricing_model'] == self.subscription_data['pricing_model']
+        assert data['billing_cycle'] == self.subscription_data['billing_cycle']
+        assert data['status'] == 'TRIAL'  # Default status with trial_days
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Should have billing period information
+        assert 'current_period_start' in data
+        assert 'current_period_end' in data
+        assert 'trial_end' in data
+
+        # Should include modules
+        assert 'modules' in data
+        assert data['modules'] == self.subscription_data['modules']
+
+    def test_create_subscription_success_tenant_admin(self):
+        """Test successful subscription creation by tenant admin."""
+        # Tenant admin creates subscription for their own tenant
+        tenant_subscription_data = self.subscription_data.copy()
+        del tenant_subscription_data['tenant_id']  # Should be inferred from context
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(tenant_subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['plan'] == tenant_subscription_data['plan']
+        assert data['tenant_id']  # Should be auto-populated
+
+    def test_create_subscription_unauthorized(self):
+        """Test subscription creation without authentication."""
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(self.subscription_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_subscription_forbidden(self):
+        """Test subscription creation by regular user (no permissions)."""
+        user_auth = {'HTTP_AUTHORIZATION': 'Bearer user_token'}
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **user_auth
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_create_subscription_missing_required_fields(self):
+        """Test subscription creation with missing required fields."""
+        incomplete_data = self.subscription_data.copy()
+        del incomplete_data['plan']
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'plan' in data.get('errors', {})
+
+    def test_create_subscription_invalid_plan(self):
+        """Test subscription creation with invalid plan."""
+        invalid_data = self.subscription_data.copy()
+        invalid_data['plan'] = 'INVALID_PLAN'
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_subscription_invalid_billing_cycle(self):
+        """Test subscription creation with invalid billing cycle."""
+        invalid_data = self.subscription_data.copy()
+        invalid_data['billing_cycle'] = 'INVALID_CYCLE'
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_subscription_duplicate_tenant(self):
+        """Test subscription creation with duplicate tenant."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same tenant should fail
+            second_response = self.client.post(
+                self.subscriptions_url,
+                data=json.dumps(self.subscription_data),
+                content_type='application/json',
+                **self.admin_auth
+            )
+            assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_subscription_without_trial(self):
+        """Test subscription creation without trial period."""
+        no_trial_data = self.subscription_data.copy()
+        del no_trial_data['trial_days']
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(no_trial_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Should be active immediately without trial
+            assert data['status'] == 'ACTIVE'
+            assert 'trial_end' not in data or data['trial_end'] is None
+
+    def test_create_subscription_with_invalid_modules(self):
+        """Test subscription creation with invalid modules."""
+        invalid_data = self.subscription_data.copy()
+        invalid_data['modules'] = ['invalid_module']
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_subscription_tenant_admin_cross_tenant(self):
+        """Test that tenant admin cannot create subscription for other tenant."""
+        # Tenant admin trying to create subscription for different tenant
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        # Should fail because tenant_id doesn't match their tenant
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_create_subscription_payment_method_validation(self):
+        """Test subscription creation with invalid payment method."""
+        invalid_data = self.subscription_data.copy()
+        invalid_data['payment_method'] = {
+            'type': 'CARD',
+            'card_last4': '4242',
+            # Missing required expiry fields
+        }
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_subscription_with_promo_code(self):
+        """Test subscription creation with promo code."""
+        promo_data = self.subscription_data.copy()
+        promo_data['promo_code'] = 'WELCOME20'
+
+        response = self.client.post(
+            self.subscriptions_url,
+            data=json.dumps(promo_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # Should include discount information
+            assert 'discount' in data
+            assert data['promo_code'] == 'WELCOME20'

backend/tests/contract/test_tenants_get.py

@@ -0,0 +1,145 @@
+"""
+Contract test for GET /tenants endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class TenantsGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.tenants_url = '/api/v1/tenants/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+    def test_get_tenants_success(self):
+        """Test successful retrieval of tenants list."""
+        response = self.client.get(
+            self.tenants_url,
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'tenants' in data
+        assert isinstance(data['tenants'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_tenants_unauthorized(self):
+        """Test tenants list retrieval without authentication."""
+        response = self.client.get(self.tenants_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_tenants_forbidden(self):
+        """Test tenants list retrieval by non-admin user."""
+        non_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer user_token'}
+
+        response = self.client.get(
+            self.tenants_url,
+            **non_admin_auth
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_get_tenants_with_pagination(self):
+        """Test tenants list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 10
+        }
+
+        response = self.client.get(
+            self.tenants_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 10
+
+    def test_get_tenants_with_search(self):
+        """Test tenants list retrieval with search parameter."""
+        params = {
+            'search': 'test'
+        }
+
+        response = self.client.get(
+            self.tenants_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned tenants should match search criteria
+        for tenant in data['tenants']:
+            assert 'test' in tenant['name'].lower()
+
+    def test_get_tenants_filter_by_status(self):
+        """Test tenants list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.tenants_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned tenants should have the specified status
+        for tenant in data['tenants']:
+            assert tenant['status'] == 'ACTIVE'
+
+    def test_get_tenants_data_structure(self):
+        """Test that tenant data structure matches the contract."""
+        response = self.client.get(
+            self.tenants_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['tenants']) > 0:
+            tenant = response.json()['tenants'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'name', 'slug', 'email', 'phone', 'business_type',
+                'subscription_plan', 'pricing_model', 'status', 'created_at'
+            ]
+
+            for field in required_fields:
+                assert field in tenant
+
+            # Field types
+            assert isinstance(tenant['id'], str)
+            assert isinstance(tenant['name'], str)
+            assert isinstance(tenant['slug'], str)
+            assert isinstance(tenant['email'], str)
+            assert tenant['business_type'] in ['RETAIL', 'HEALTHCARE', 'EDUCATION', 'LOGISTICS', 'BEAUTY']
+            assert tenant['subscription_plan'] in ['STARTER', 'GROWTH', 'PRO', 'ENTERPRISE']
+            assert tenant['pricing_model'] in ['SUBSCRIPTION', 'PERPETUAL']
+            assert tenant['status'] in ['PENDING', 'ACTIVE', 'SUSPENDED', 'TERMINATED']

backend/tests/contract/test_tenants_post.py

@@ -0,0 +1,182 @@
+"""
+Contract test for POST /tenants endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class TenantsPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.tenants_url = '/api/v1/tenants/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Valid tenant data
+        self.tenant_data = {
+            'name': 'Test Business Sdn Bhd',
+            'email': 'business@test.com',
+            'phone': '+60123456789',
+            'address': {
+                'street': '123 Business Street',
+                'city': 'Kuala Lumpur',
+                'state': 'Wilayah Persekutuan',
+                'postal_code': '50000',
+                'country': 'Malaysia'
+            },
+            'business_type': 'RETAIL',
+            'subscription_plan': 'STARTER',
+            'pricing_model': 'SUBSCRIPTION'
+        }
+
+    def test_create_tenant_success(self):
+        """Test successful tenant creation."""
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['name'] == self.tenant_data['name']
+        assert data['email'] == self.tenant_data['email']
+        assert data['business_type'] == self.tenant_data['business_type']
+        assert data['subscription_plan'] == self.tenant_data['subscription_plan']
+        assert data['pricing_model'] == self.tenant_data['pricing_model']
+        assert data['status'] == 'PENDING'  # Default status
+
+        # Should have generated slug
+        assert 'slug' in data
+        assert data['slug'] == 'test-business-sdn-bhd'
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+    def test_create_tenant_unauthorized(self):
+        """Test tenant creation without authentication."""
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(self.tenant_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_tenant_forbidden(self):
+        """Test tenant creation by non-admin user."""
+        non_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer user_token'}
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **non_admin_auth
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_create_tenant_missing_required_fields(self):
+        """Test tenant creation with missing required fields."""
+        incomplete_data = self.tenant_data.copy()
+        del incomplete_data['name']
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'name' in data.get('errors', {})
+
+    def test_create_tenant_invalid_email(self):
+        """Test tenant creation with invalid email format."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['email'] = 'invalid-email'
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_tenant_invalid_business_type(self):
+        """Test tenant creation with invalid business type."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['business_type'] = 'INVALID_TYPE'
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_tenant_duplicate_email(self):
+        """Test tenant creation with duplicate email."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same email should fail
+            second_response = self.client.post(
+                self.tenants_url,
+                data=json.dumps(self.tenant_data),
+                content_type='application/json',
+                **self.admin_auth
+            )
+            assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_tenant_invalid_address(self):
+        """Test tenant creation with invalid address format."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['address'] = 'invalid address format'
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_tenant_malformed_address(self):
+        """Test tenant creation with malformed address JSON."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['address'] = {'street': '123 Street'}  # Missing required fields
+
+        response = self.client.post(
+            self.tenants_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST

backend/tests/contract/test_users_get.py

@@ -0,0 +1,185 @@
+"""
+Contract test for GET /users endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class UsersGetContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.users_url = '/api/v1/users/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Regular user authentication header
+        self.user_auth = {'HTTP_AUTHORIZATION': 'Bearer user_token'}
+
+    def test_get_users_success_admin(self):
+        """Test successful retrieval of users list by admin."""
+        response = self.client.get(
+            self.users_url,
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'users' in data
+        assert isinstance(data['users'], list)
+
+        # Check pagination structure
+        assert 'pagination' in data
+        pagination = data['pagination']
+        assert 'page' in pagination
+        assert 'limit' in pagination
+        assert 'total' in pagination
+        assert 'pages' in pagination
+
+    def test_get_users_success_tenant_admin(self):
+        """Test successful retrieval of users list by tenant admin."""
+        response = self.client.get(
+            self.users_url,
+            **self.user_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert 'users' in data
+        assert isinstance(data['users'], list)
+
+        # Tenant admin should only see users from their tenant
+        # This will be validated once implementation exists
+
+    def test_get_users_unauthorized(self):
+        """Test users list retrieval without authentication."""
+        response = self.client.get(self.users_url)
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_get_users_with_pagination(self):
+        """Test users list retrieval with pagination parameters."""
+        params = {
+            'page': 2,
+            'limit': 10
+        }
+
+        response = self.client.get(
+            self.users_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        assert data['pagination']['page'] == 2
+        assert data['pagination']['limit'] == 10
+
+    def test_get_users_with_search(self):
+        """Test users list retrieval with search parameter."""
+        params = {
+            'search': 'john'
+        }
+
+        response = self.client.get(
+            self.users_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned users should match search criteria
+        for user in data['users']:
+            assert 'john' in user['name'].lower() or 'john' in user['email'].lower()
+
+    def test_get_users_filter_by_role(self):
+        """Test users list retrieval filtered by role."""
+        params = {
+            'role': 'TENANT_ADMIN'
+        }
+
+        response = self.client.get(
+            self.users_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned users should have the specified role
+        for user in data['users']:
+            assert user['role'] == 'TENANT_ADMIN'
+
+    def test_get_users_filter_by_status(self):
+        """Test users list retrieval filtered by status."""
+        params = {
+            'status': 'ACTIVE'
+        }
+
+        response = self.client.get(
+            self.users_url,
+            data=params,
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+
+        data = response.json()
+        # All returned users should have the specified status
+        for user in data['users']:
+            assert user['status'] == 'ACTIVE'
+
+    def test_get_users_tenant_isolation(self):
+        """Test that tenant admin can only see users from their tenant."""
+        # This test verifies tenant isolation for user data
+        response = self.client.get(
+            self.users_url,
+            **self.user_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK:
+            data = response.json()
+            # For tenant users, all returned users should belong to their tenant
+            # This will be validated once implementation exists
+            pass
+
+    def test_get_users_data_structure(self):
+        """Test that user data structure matches the contract."""
+        response = self.client.get(
+            self.users_url,
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_200_OK and len(response.json()['users']) > 0:
+            user = response.json()['users'][0]
+
+            # Required fields according to contract
+            required_fields = [
+                'id', 'email', 'name', 'role', 'status',
+                'tenant_id', 'created_at', 'last_login'
+            ]
+
+            for field in required_fields:
+                assert field in user
+
+            # Field types and enums
+            assert isinstance(user['id'], str)
+            assert isinstance(user['email'], str)
+            assert isinstance(user['name'], str)
+            assert user['role'] in ['SUPER_ADMIN', 'TENANT_ADMIN', 'MANAGER', 'STAFF', 'VIEWER']
+            assert user['status'] in ['ACTIVE', 'INACTIVE', 'PENDING', 'SUSPENDED']
+            assert isinstance(user['tenant_id'], str)

backend/tests/contract/test_users_post.py

@@ -0,0 +1,251 @@
+"""
+Contract test for POST /users endpoint.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class UsersPostContractTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.users_url = '/api/v1/users/'
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer admin_token'}
+
+        # Tenant admin authentication header
+        self.tenant_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_admin_token'}
+
+        # Valid user data
+        self.user_data = {
+            'email': 'john.doe@example.com',
+            'name': 'John Doe',
+            'password': 'SecurePassword123!',
+            'role': 'STAFF',
+            'department': 'Operations',
+            'phone': '+60123456789',
+            'profile': {
+                'position': 'Manager',
+                'skills': ['leadership', 'operations'],
+                'experience_years': 5
+            }
+        }
+
+    def test_create_user_success_admin(self):
+        """Test successful user creation by super admin."""
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['email'] == self.user_data['email']
+        assert data['name'] == self.user_data['name']
+        assert data['role'] == self.user_data['role']
+        assert data['status'] == 'PENDING'  # Default status for new users
+        assert data['department'] == self.user_data['department']
+        assert data['phone'] == self.user_data['phone']
+
+        # Should have generated tenant_id from context
+        assert 'tenant_id' in data
+
+        # Should have timestamps
+        assert 'created_at' in data
+        assert 'updated_at' in data
+
+        # Password should not be returned
+        assert 'password' not in data
+
+    def test_create_user_success_tenant_admin(self):
+        """Test successful user creation by tenant admin."""
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        # This should fail before implementation
+        assert response.status_code == status.HTTP_201_CREATED
+
+        data = response.json()
+        assert 'id' in data
+        assert data['email'] == self.user_data['email']
+        assert data['name'] == self.user_data['name']
+
+        # Tenant admin cannot create SUPER_ADMIN users
+        # This will be validated once implementation exists
+
+    def test_create_user_unauthorized(self):
+        """Test user creation without authentication."""
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_create_user_forbidden(self):
+        """Test user creation by regular user (no permissions)."""
+        user_auth = {'HTTP_AUTHORIZATION': 'Bearer user_token'}
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **user_auth
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_create_user_missing_required_fields(self):
+        """Test user creation with missing required fields."""
+        incomplete_data = self.user_data.copy()
+        del incomplete_data['email']
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(incomplete_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+        data = response.json()
+        assert 'email' in data.get('errors', {})
+
+    def test_create_user_invalid_email(self):
+        """Test user creation with invalid email format."""
+        invalid_data = self.user_data.copy()
+        invalid_data['email'] = 'invalid-email'
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_user_weak_password(self):
+        """Test user creation with weak password."""
+        invalid_data = self.user_data.copy()
+        invalid_data['password'] = '123'
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_user_invalid_role(self):
+        """Test user creation with invalid role."""
+        invalid_data = self.user_data.copy()
+        invalid_data['role'] = 'INVALID_ROLE'
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_user_duplicate_email(self):
+        """Test user creation with duplicate email."""
+        # First request should succeed (if implemented)
+        first_response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if first_response.status_code == status.HTTP_201_CREATED:
+            # Second request with same email should fail
+            second_response = self.client.post(
+                self.users_url,
+                data=json.dumps(self.user_data),
+                content_type='application/json',
+                **self.admin_auth
+            )
+            assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_user_tenant_admin_cannot_create_super_admin(self):
+        """Test that tenant admin cannot create super admin users."""
+        super_admin_data = self.user_data.copy()
+        super_admin_data['role'] = 'SUPER_ADMIN'
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(super_admin_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    def test_create_user_with_profile_data(self):
+        """Test user creation with profile information."""
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            assert 'profile' in data
+            profile = data['profile']
+            assert profile['position'] == self.user_data['profile']['position']
+            assert profile['skills'] == self.user_data['profile']['skills']
+            assert profile['experience_years'] == self.user_data['profile']['experience_years']
+
+    def test_create_user_malformed_profile(self):
+        """Test user creation with malformed profile JSON."""
+        invalid_data = self.user_data.copy()
+        invalid_data['profile'] = 'invalid profile format'
+
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_create_user_tenant_isolation(self):
+        """Test that user creation respects tenant isolation."""
+        response = self.client.post(
+            self.users_url,
+            data=json.dumps(self.user_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            data = response.json()
+            # User should be created in the tenant admin's tenant
+            # This will be validated once implementation exists
+            assert 'tenant_id' in data

backend/tests/integration/test_healthcare_operations.py

@@ -0,0 +1,626 @@
+"""
+Integration test for healthcare module operations.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+from datetime import datetime, timedelta
+
+
+class HealthcareOperationsIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Test patient data
+        self.patient_data = {
+            'ic_number': '900101-10-1234',
+            'name': 'Ahmad bin Hassan',
+            'gender': 'MALE',
+            'date_of_birth': '1990-01-01',
+            'phone': '+60123456789',
+            'email': 'ahmad.hassan@example.com',
+            'address': {
+                'street': '123 Jalan Healthcare',
+                'city': 'Kuala Lumpur',
+                'state': 'Wilayah Persekutuan',
+                'postal_code': '50400',
+                'country': 'Malaysia'
+            },
+            'blood_type': 'O+',
+            'allergies': ['Penicillin'],
+            'medications': ['Metformin 500mg']
+        }
+
+        # Test doctor data
+        self.doctor_data = {
+            'name': 'Dr. Sarah Johnson',
+            'specialization': 'General Practitioner',
+            'license_number': 'L12345',
+            'department': 'Primary Care',
+            'phone': '+60312345678',
+            'email': 'sarah.johnson@hospital.com'
+        }
+
+    def test_complete_patient_workflow(self):
+        """Test complete patient workflow from registration to treatment."""
+        # Step 1: Patient registration (should fail before implementation)
+        patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert patient_response.status_code == status.HTTP_201_CREATED
+        patient_data = patient_response.json()
+
+        # Verify patient structure
+        assert 'id' in patient_data
+        assert patient_data['ic_number'] == self.patient_data['ic_number']
+        assert patient_data['name'] == self.patient_data['name']
+        assert patient_data['age'] == 34  # Calculated from DOB
+        assert patient_data['status'] == 'ACTIVE'
+
+        # Step 2: Create doctor
+        doctor_response = self.client.post(
+            '/api/v1/healthcare/doctors/',
+            data=json.dumps(self.doctor_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert doctor_response.status_code == status.HTTP_201_CREATED
+        doctor_data = doctor_response.json()
+
+        # Step 3: Schedule appointment
+        appointment_data = {
+            'patient_id': patient_data['id'],
+            'doctor_id': doctor_data['id'],
+            'appointment_datetime': '2024-02-15T14:30:00+08:00',
+            'duration': 30,
+            'type': 'CONSULTATION',
+            'reason': 'Regular checkup for diabetes management',
+            'priority': 'NORMAL'
+        }
+
+        appointment_response = self.client.post(
+            '/api/v1/healthcare/appointments/',
+            data=json.dumps(appointment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert appointment_response.status_code == status.HTTP_201_CREATED
+        appointment_data = appointment_response.json()
+
+        assert appointment_data['status'] == 'SCHEDULED'
+
+        # Step 4: Update appointment status to in-progress
+        status_update_response = self.client.put(
+            f'/api/v1/healthcare/appointments/{appointment_data["id"]}/status/',
+            data=json.dumps({'status': 'IN_PROGRESS'}),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert status_update_response.status_code == status.HTTP_200_OK
+
+        # Step 5: Create medical record
+        medical_record_data = {
+            'patient_id': patient_data['id'],
+            'appointment_id': appointment_data['id'],
+            'doctor_id': doctor_data['id'],
+            'diagnosis': 'Type 2 Diabetes - well controlled',
+            'treatment': 'Continue current medication regimen',
+            'prescriptions': [
+                {
+                    'medication': 'Metformin',
+                    'dosage': '500mg',
+                    'frequency': 'Twice daily',
+                    'duration': '30 days',
+                    'instructions': 'Take with meals'
+                }
+            ],
+            'vitals': {
+                'blood_pressure': '120/80',
+                'heart_rate': 72,
+                'temperature': 36.5,
+                'weight': 75.5,
+                'height': 175.0
+            },
+            'notes': 'Patient reports good compliance with medication. Blood sugar levels well controlled.'
+        }
+
+        record_response = self.client.post(
+            '/api/v1/healthcare/medical-records/',
+            data=json.dumps(medical_record_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert record_response.status_code == status.HTTP_201_CREATED
+        record_data = record_response.json()
+
+        # Step 6: Complete appointment
+        complete_response = self.client.put(
+            f'/api/v1/healthcare/appointments/{appointment_data["id"]}/status/',
+            data=json.dumps({'status': 'COMPLETED'}),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert complete_response.status_code == status.HTTP_200_OK
+
+        # Step 7: Schedule follow-up appointment
+        follow_up_data = {
+            'patient_id': patient_data['id'],
+            'doctor_id': doctor_data['id'],
+            'appointment_datetime': '2024-03-15T14:30:00+08:00',
+            'duration': 20,
+            'type': 'FOLLOW_UP',
+            'reason': 'Diabetes follow-up'
+        }
+
+        follow_up_response = self.client.post(
+            '/api/v1/healthcare/appointments/',
+            data=json.dumps(follow_up_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert follow_up_response.status_code == status.HTTP_201_CREATED
+
+    def test_medical_records_management(self):
+        """Test medical records management and history."""
+        # Create patient first
+        patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert patient_response.status_code == status.HTTP_201_CREATED
+        patient_data = patient_response.json()
+
+        # Create multiple medical records over time
+        records_data = [
+            {
+                'diagnosis': 'Hypertension',
+                'treatment': 'Lifestyle modifications',
+                'prescriptions': [
+                    {
+                        'medication': 'Lisinopril',
+                        'dosage': '10mg',
+                        'frequency': 'Once daily'
+                    }
+                ]
+            },
+            {
+                'diagnosis': 'Annual checkup - normal',
+                'treatment': 'Continue healthy lifestyle',
+                'vitals': {
+                    'blood_pressure': '118/76',
+                    'heart_rate': 68,
+                    'cholesterol': 180
+                }
+            }
+        ]
+
+        created_records = []
+        for record_data in records_data:
+            full_record_data = {
+                'patient_id': patient_data['id'],
+                'doctor_id': 'doctor-001',
+                'diagnosis': record_data['diagnosis'],
+                'treatment': record_data['treatment'],
+                **{k: v for k, v in record_data.items() if k not in ['diagnosis', 'treatment']}
+            }
+
+            record_response = self.client.post(
+                '/api/v1/healthcare/medical-records/',
+                data=json.dumps(full_record_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+
+            assert record_response.status_code == status.HTTP_201_CREATED
+            created_records.append(record_response.json())
+
+        # Test medical history retrieval
+        history_response = self.client.get(
+            f'/api/v1/healthcare/patients/{patient_data["id"]}/medical-history/',
+            **self.tenant_auth
+        )
+
+        assert history_response.status_code == status.HTTP_200_OK
+        history_data = history_response.json()
+
+        assert 'medical_records' in history_data
+        assert 'conditions' in history_data
+        assert 'medications' in history_data
+        assert 'allergies' in history_data
+
+        # Verify records are chronological
+        records = history_data['medical_records']
+        assert len(records) == len(created_records)
+
+        # Test record search and filtering
+        search_response = self.client.get(
+            f'/api/v1/healthcare/medical-records/',
+            data={'patient_id': patient_data['id'], 'diagnosis': 'Hypertension'},
+            **self.tenant_auth
+        )
+
+        assert search_response.status_code == status.HTTP_200_OK
+        search_results = search_response.json()['records']
+
+        assert len(search_results) > 0
+        assert any('Hypertension' in record['diagnosis'] for record in search_results)
+
+    def test_prescription_management(self):
+        """Test prescription management and dispensing."""
+        # Create patient
+        patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert patient_response.status_code == status.HTTP_201_CREATED
+        patient_data = patient_response.json()
+
+        # Create prescription
+        prescription_data = {
+            'patient_id': patient_data['id'],
+            'doctor_id': 'doctor-001',
+            'medications': [
+                {
+                    'name': 'Amoxicillin',
+                    'dosage': '500mg',
+                    'frequency': 'Three times daily',
+                    'duration': '7 days',
+                    'quantity': 21,
+                    'instructions': 'Take after meals',
+                    'refills_allowed': 0
+                },
+                {
+                    'name': 'Ibuprofen',
+                    'dosage': '400mg',
+                    'frequency': 'As needed for pain',
+                    'duration': '3 days',
+                    'quantity': 9,
+                    'instructions': 'Take with food',
+                    'refills_allowed': 1
+                }
+            ],
+            'diagnosis': 'Bacterial infection',
+            'notes': 'Complete full course of antibiotics'
+        }
+
+        prescription_response = self.client.post(
+            '/api/v1/healthcare/prescriptions/',
+            data=json.dumps(prescription_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert prescription_response.status_code == status.HTTP_201_CREATED
+        prescription_data = prescription_response.json()
+
+        # Test prescription status management
+        dispense_data = {
+            'dispensed_by': 'pharmacist-001',
+            'dispensed_at': datetime.now().isoformat(),
+            'notes': 'Patient counseled on medication use'
+        }
+
+        dispense_response = self.client.post(
+            f'/api/v1/healthcare/prescriptions/{prescription_data["id"]}/dispense/',
+            data=json.dumps(dispense_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert dispense_response.status_code == status.HTTP_200_OK
+
+        # Test refill request
+        refill_response = self.client.post(
+            f'/api/v1/healthcare/prescriptions/{prescription_data["id"]}/refill/',
+            data=json.dumps({}),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert refill_response.status_code == status.HTTP_200_OK
+
+    def test_laboratory_and_imaging_orders(self):
+        """Test laboratory and imaging order management."""
+        # Create patient
+        patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(self.patient_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert patient_response.status_code == status.HTTP_201_CREATED
+        patient_data = patient_response.json()
+
+        # Create lab order
+        lab_order_data = {
+            'patient_id': patient_data['id'],
+            'doctor_id': 'doctor-001',
+            'tests': [
+                {
+                    'test_code': 'CBC',
+                    'test_name': 'Complete Blood Count',
+                    'priority': 'ROUTINE',
+                    'clinical_indication': 'Annual checkup'
+                },
+                {
+                    'test_code': 'HBA1C',
+                    'test_name': 'Hemoglobin A1C',
+                    'priority': 'ROUTINE',
+                    'clinical_indication': 'Diabetes monitoring'
+                }
+            ],
+            'notes': 'Patient fasting for 12 hours'
+        }
+
+        lab_order_response = self.client.post(
+            '/api/v1/healthcare/laboratory-orders/',
+            data=json.dumps(lab_order_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert lab_order_response.status_code == status.HTTP_201_CREATED
+        lab_order = lab_order_response.json()
+
+        # Update lab results
+        results_data = {
+            'results': [
+                {
+                    'test_code': 'CBC',
+                    'result_value': 'Normal',
+                    'reference_range': '4.5-5.5 x 10^12/L',
+                    'units': 'x 10^12/L',
+                    'status': 'NORMAL'
+                },
+                {
+                    'test_code': 'HBA1C',
+                    'result_value': '6.2',
+                    'reference_range': '< 5.7%',
+                    'units': '%',
+                    'status': 'ABNORMAL',
+                    'notes': 'Slightly elevated - monitor'
+                }
+            ],
+            'interpreted_by': 'Dr. Lab Specialist',
+            'interpretation': 'HbA1c shows prediabetes range'
+        }
+
+        results_response = self.client.post(
+            f'/api/v1/healthcare/laboratory-orders/{lab_order["id"]}/results/',
+            data=json.dumps(results_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert results_response.status_code == status.HTTP_200_OK
+
+    def test_billing_and_insurance_integration(self):
+        """Test billing and insurance claim processing."""
+        # Create patient with insurance
+        patient_with_insurance = self.patient_data.copy()
+        patient_with_insurance['insurance'] = {
+            'provider': 'Malaysia National Insurance',
+            'policy_number': 'MNI-123456789',
+            'coverage_details': 'Full coverage',
+            'expiry_date': '2024-12-31'
+        }
+
+        patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(patient_with_insurance),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert patient_response.status_code == status.HTTP_201_CREATED
+        patient_data = patient_response.json()
+
+        # Create consultation and generate bill
+        billing_data = {
+            'patient_id': patient_data['id'],
+            'services': [
+                {
+                    'service_code': 'CONSULT_GP',
+                    'description': 'General Practitioner Consultation',
+                    'amount': 150.00,
+                    'quantity': 1
+                },
+                {
+                    'service_code': 'LAB_CBC',
+                    'description': 'Complete Blood Count',
+                    'amount': 50.00,
+                    'quantity': 1
+                }
+            ],
+            'insurance_claim': {
+                'provider': patient_data['insurance']['provider'],
+                'policy_number': patient_data['insurance']['policy_number'],
+                'pre_authorization_code': 'PA-2024-001'
+            }
+        }
+
+        billing_response = self.client.post(
+            '/api/v1/healthcare/billing/',
+            data=json.dumps(billing_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert billing_response.status_code == status.HTTP_201_CREATED
+        billing_data = billing_response.json()
+
+        # Verify insurance claim processing
+        assert 'insurance_coverage' in billing_data
+        assert 'patient_responsibility' in billing_data
+        assert 'claim_status' in billing_data
+
+    def test_healthcare_compliance_and_reporting(self):
+        """Test healthcare compliance and reporting features."""
+        # Test PDPA compliance (Personal Data Protection Act)
+        compliance_response = self.client.get(
+            '/api/v1/healthcare/compliance/data-protection/',
+            **self.tenant_auth
+        )
+
+        assert compliance_response.status_code == status.HTTP_200_OK
+        compliance_data = compliance_response.json()
+
+        assert 'consent_records' in compliance_data
+        assert 'data_access_logs' in compliance_data
+        assert 'retention_policies' in compliance_data
+
+        # Test clinical reporting
+        clinical_report_response = self.client.get(
+            '/api/v1/healthcare/reports/clinical/',
+            data={
+                'period': 'monthly',
+                'year': 2024,
+                'month': 1
+            },
+            **self.tenant_auth
+        )
+
+        assert clinical_report_response.status_code == status.HTTP_200_OK
+        clinical_report = clinical_report_response.json()
+
+        assert 'patient_visits' in clinical_report
+        assert 'common_diagnoses' in clinical_report
+        assert 'prescription_trends' in clinical_report
+
+        # Test adverse event reporting
+        adverse_event_data = {
+            'patient_id': 'patient-001',
+            'event_type': 'MEDICATION_ERROR',
+            'description': 'Wrong dosage administered',
+            'severity': 'MINOR',
+            'date_occurred': datetime.now().isoformat(),
+            'reported_by': 'nurse-001',
+            'actions_taken': 'Corrected dosage, patient monitored'
+        }
+
+        adverse_response = self.client.post(
+            '/api/v1/healthcare/adverse-events/',
+            data=json.dumps(adverse_event_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert adverse_response.status_code == status.HTTP_201_CREATED
+
+    def test_telemedicine_integration(self):
+        """Test telemedicine and virtual consultation features."""
+        # Create virtual appointment
+        virtual_appointment_data = {
+            'patient_id': 'patient-001',
+            'doctor_id': 'doctor-001',
+            'appointment_datetime': '2024-02-15T15:00:00+08:00',
+            'duration': 20,
+            'type': 'CONSULTATION',
+            'is_virtual': True,
+            'virtual_consultation': {
+                'platform': 'ZOOM',
+                'link': 'https://zoom.us/j/123456789',
+                'instructions': 'Join 5 minutes early, test audio/video',
+                'meeting_id': '123456789',
+                'password': 'health2024'
+            },
+            'reason': 'Follow-up consultation'
+        }
+
+        virtual_response = self.client.post(
+            '/api/v1/healthcare/appointments/',
+            data=json.dumps(virtual_appointment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert virtual_response.status_code == status.HTTP_201_CREATED
+        virtual_appointment = virtual_response.json()
+
+        assert virtual_appointment['is_virtual'] is True
+        assert 'virtual_consultation' in virtual_appointment
+
+        # Test telemedicine session logging
+        session_log_data = {
+            'appointment_id': virtual_appointment['id'],
+            'start_time': '2024-02-15T15:00:00Z',
+            'end_time': '2024-02-15T15:18:00Z',
+            'duration_minutes': 18,
+            'connection_quality': 'GOOD',
+            'technical_issues': None,
+            'notes': 'Successful virtual consultation'
+        }
+
+        session_log_response = self.client.post(
+            '/api/v1/healthcare/telemedicine/session-logs/',
+            data=json.dumps(session_log_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert session_log_response.status_code == status.HTTP_201_CREATED
+
+    def test_emergency_management(self):
+        """Test emergency case management and triage."""
+        # Create emergency appointment
+        emergency_data = {
+            'patient_id': 'patient-001',
+            'doctor_id': 'doctor-emergency',
+            'appointment_datetime': datetime.now().isoformat(),
+            'duration': 60,
+            'type': 'EMERGENCY',
+            'priority': 'URGENT',
+            'reason': 'Chest pain and shortness of breath',
+            'triage_level': 'YELLOW'
+        }
+
+        emergency_response = self.client.post(
+            '/api/v1/healthcare/appointments/',
+            data=json.dumps(emergency_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert emergency_response.status_code == status.HTTP_201_CREATED
+        emergency_appointment = emergency_response.json()
+
+        assert emergency_appointment['type'] == 'EMERGENCY'
+        assert emergency_appointment['priority'] == 'URGENT'
+
+        # Test emergency response protocol
+        protocol_response = self.client.get(
+            f'/api/v1/healthcare/emergency/protocols/{emergency_appointment["triage_level"]}/',
+            **self.tenant_auth
+        )
+
+        assert protocol_response.status_code == status.HTTP_200_OK
+        protocol_data = protocol_response.json()
+
+        assert 'response_time_target' in protocol_data
+        assert 'required_actions' in protocol_data
+        assert 'staffing_requirements' in protocol_data

backend/tests/integration/test_retail_operations.py

@@ -0,0 +1,579 @@
+"""
+Integration test for retail module operations.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+from datetime import datetime, timedelta
+
+
+class RetailOperationsIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Tenant authentication header
+        self.tenant_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_token'}
+
+        # Test product data
+        self.product_data = {
+            'sku': 'LPT-PRO-001',
+            'name': 'Professional Laptop 15"',
+            'description': 'High-performance laptop for business use',
+            'category': 'ELECTRONICS',
+            'price': 3499.99,
+            'cost': 2800.00,
+            'stock_quantity': 25,
+            'barcode': '1234567890123',
+            'brand': 'TechBrand',
+            'model': 'PRO-15-2024',
+            'tax_rate': 6.0
+        }
+
+        # Test customer data
+        self.customer_data = {
+            'name': 'John Customer',
+            'email': 'john.customer@example.com',
+            'phone': '+60123456789',
+            'address': {
+                'street': '123 Customer Street',
+                'city': 'Kuala Lumpur',
+                'state': 'Wilayah Persekutuan',
+                'postal_code': '50000',
+                'country': 'Malaysia'
+            }
+        }
+
+    def test_complete_retail_workflow(self):
+        """Test complete retail workflow from product creation to sales reporting."""
+        # Step 1: Create product (should fail before implementation)
+        product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(self.product_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert product_response.status_code == status.HTTP_201_CREATED
+        product_data = product_response.json()
+
+        # Verify product structure
+        assert 'id' in product_data
+        assert product_data['sku'] == self.product_data['sku']
+        assert product_data['stock_quantity'] == self.product_data['stock_quantity']
+        assert product_data['status'] == 'ACTIVE'
+
+        # Step 2: Create additional products for inventory testing
+        additional_products = [
+            {
+                'sku': 'MOU-WRL-001',
+                'name': 'Wireless Mouse',
+                'category': 'ELECTRONICS',
+                'price': 89.99,
+                'cost': 45.00,
+                'stock_quantity': 50
+            },
+            {
+                'sku': 'KEY-MEC-001',
+                'name': 'Mechanical Keyboard',
+                'category': 'ELECTRONICS',
+                'price': 299.99,
+                'cost': 180.00,
+                'stock_quantity': 30
+            }
+        ]
+
+        created_products = []
+        for prod_data in additional_products:
+            prod_response = self.client.post(
+                '/api/v1/retail/products/',
+                data=json.dumps(prod_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+            assert prod_response.status_code == status.HTTP_201_CREATED
+            created_products.append(prod_response.json())
+
+        # Step 3: Process multiple sales transactions
+        sales_transactions = [
+            {
+                'customer': self.customer_data,
+                'items': [
+                    {
+                        'product_id': product_data['id'],
+                        'sku': product_data['sku'],
+                        'quantity': 2,
+                        'unit_price': product_data['price']
+                    },
+                    {
+                        'product_id': created_products[0]['id'],
+                        'sku': created_products[0]['sku'],
+                        'quantity': 1,
+                        'unit_price': created_products[0]['price']
+                    }
+                ],
+                'payment': {
+                    'method': 'CARD',
+                    'amount_paid': 7290.00,
+                    'reference_number': 'CARD-001'
+                }
+            },
+            {
+                'customer': {
+                    'name': 'Jane Buyer',
+                    'email': 'jane@example.com',
+                    'phone': '+60198765432'
+                },
+                'items': [
+                    {
+                        'product_id': created_products[1]['id'],
+                        'sku': created_products[1]['sku'],
+                        'quantity': 3,
+                        'unit_price': created_products[1]['price']
+                    }
+                ],
+                'payment': {
+                    'method': 'CASH',
+                    'amount_paid': 900.00,
+                    'reference_number': 'CASH-001'
+                }
+            }
+        ]
+
+        created_sales = []
+        for sale_data in sales_transactions:
+            sale_response = self.client.post(
+                '/api/v1/retail/sales/',
+                data=json.dumps(sale_data),
+                content_type='application/json',
+                **self.tenant_auth
+            )
+
+            assert sale_response.status_code == status.HTTP_201_CREATED
+            created_sales.append(sale_response.json())
+
+        # Step 4: Verify inventory updates after sales
+        inventory_check_response = self.client.get(
+            f'/api/v1/retail/products/{product_data["id"]}/',
+            **self.tenant_auth
+        )
+
+        assert inventory_check_response.status_code == status.HTTP_200_OK
+        updated_product = inventory_check_response.json()
+
+        # Stock should be reduced by sold quantity
+        expected_stock = self.product_data['stock_quantity'] - 2  # 2 laptops sold
+        assert updated_product['stock_quantity'] == expected_stock
+
+        # Step 5: Test sales reporting
+        sales_report_response = self.client.get(
+            '/api/v1/retail/reports/sales/',
+            data={
+                'start_date': (datetime.now() - timedelta(days=7)).isoformat(),
+                'end_date': datetime.now().isoformat()
+            },
+            **self.tenant_auth
+        )
+
+        assert sales_report_response.status_code == status.HTTP_200_OK
+        sales_report = sales_report_response.json()
+
+        assert 'total_sales' in sales_report
+        assert 'total_revenue' in sales_report
+        assert 'transactions_count' in sales_report
+        assert 'top_products' in sales_report
+
+        # Verify report data
+        assert sales_report['transactions_count'] == len(created_sales)
+        assert sales_report['total_revenue'] > 0
+
+        # Step 6: Test inventory reporting
+        inventory_report_response = self.client.get(
+            '/api/v1/retail/reports/inventory/',
+            **self.tenant_auth
+        )
+
+        assert inventory_report_response.status_code == status.HTTP_200_OK
+        inventory_report = inventory_report_response.json()
+
+        assert 'total_products' in inventory_report
+        assert 'low_stock_items' in inventory_report
+        assert 'total_value' in inventory_report
+
+        # Step 7: Test product search and filtering
+        search_response = self.client.get(
+            '/api/v1/retail/products/',
+            data={'search': 'laptop', 'category': 'ELECTRONICS'},
+            **self.tenant_auth
+        )
+
+        assert search_response.status_code == status.HTTP_200_OK
+        search_results = search_response.json()['products']
+
+        # Should find the laptop product
+        assert len(search_results) > 0
+        assert any(product['id'] == product_data['id'] for product in search_results)
+
+    def test_inventory_management_operations(self):
+        """Test inventory management operations."""
+        # Create product first
+        product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(self.product_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert product_response.status_code == status.HTTP_201_CREATED
+        product_data = product_response.json()
+
+        # Step 1: Stock adjustment
+        adjustment_data = {
+            'type': 'ADDITION',
+            'quantity': 10,
+            'reason': 'New stock received',
+            'reference': 'PO-2024-001',
+            'unit_cost': 2750.00
+        }
+
+        adjustment_response = self.client.post(
+            f'/api/v1/retail/products/{product_data["id"]}/inventory/',
+            data=json.dumps(adjustment_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert adjustment_response.status_code == status.HTTP_200_OK
+
+        # Verify stock was updated
+        updated_product_response = self.client.get(
+            f'/api/v1/retail/products/{product_data["id"]}/',
+            **self.tenant_auth
+        )
+
+        assert updated_product_response.status_code == status.HTTP_200_OK
+        updated_product = updated_product_response.json()
+
+        expected_stock = self.product_data['stock_quantity'] + 10
+        assert updated_product['stock_quantity'] == expected_stock
+
+        # Step 2: Stock transfer
+        transfer_data = {
+            'quantity': 5,
+            'from_location': 'Warehouse A',
+            'to_location': 'Store Front',
+            'reason': 'Restocking store'
+        }
+
+        transfer_response = self.client.post(
+            f'/api/v1/retail/products/{product_data["id"]}/transfer/',
+            data=json.dumps(transfer_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert transfer_response.status_code == status.HTTP_200_OK
+
+        # Step 3: Low stock alerts
+        # Create product with low stock
+        low_stock_product = self.product_data.copy()
+        low_stock_product['sku'] = 'LOW-STOCK-001'
+        low_stock_product['stock_quantity'] = 2
+
+        low_stock_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(low_stock_product),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert low_stock_response.status_code == status.HTTP_201_CREATED
+
+        # Check low stock report
+        low_stock_report_response = self.client.get(
+            '/api/v1/retail/reports/low-stock/',
+            **self.tenant_auth
+        )
+
+        assert low_stock_report_response.status_code == status.HTTP_200_OK
+        low_stock_report = low_stock_report_response.json()
+
+        assert 'low_stock_items' in low_stock_report
+        assert len(low_stock_report['low_stock_items']) > 0
+
+    def test_product_variant_management(self):
+        """Test product variant management."""
+        # Create parent product with variants
+        parent_product = self.product_data.copy()
+        parent_product['variants'] = [
+            {
+                'sku': 'LPT-PRO-001-BLK',
+                'name': 'Professional Laptop 15" - Black',
+                'attributes': {'color': 'Black', 'storage': '512GB SSD'},
+                'price_adjustment': 0,
+                'stock_quantity': 10
+            },
+            {
+                'sku': 'LPT-PRO-001-SLV',
+                'name': 'Professional Laptop 15" - Silver',
+                'attributes': {'color': 'Silver', 'storage': '1TB SSD'},
+                'price_adjustment': 200,
+                'stock_quantity': 8
+            }
+        ]
+
+        product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(parent_product),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert product_response.status_code == status.HTTP_201_CREATED
+        created_product = product_response.json()
+
+        # Verify variants were created
+        assert 'variants' in created_product
+        assert len(created_product['variants']) == 2
+
+        # Test variant operations
+        variant = created_product['variants'][0]
+
+        # Update variant stock
+        variant_stock_update = {
+            'stock_quantity': 15,
+            'reason': 'New stock received'
+        }
+
+        variant_update_response = self.client.put(
+            f'/api/v1/retail/products/{created_product["id"]}/variants/{variant["sku"]}/',
+            data=json.dumps(variant_stock_update),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert variant_update_response.status_code == status.HTTP_200_OK
+
+    def test_customer_management(self):
+        """Test customer management operations."""
+        # Create customer
+        customer_response = self.client.post(
+            '/api/v1/retail/customers/',
+            data=json.dumps(self.customer_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert customer_response.status_code == status.HTTP_201_CREATED
+        customer_data = customer_response.json()
+
+        # Step 1: Customer purchase history
+        # Create a sale for this customer
+        sale_data = {
+            'customer_id': customer_data['id'],
+            'items': [
+                {
+                    'product_id': 'product-001',
+                    'sku': 'TEST-001',
+                    'quantity': 1,
+                    'unit_price': 99.99
+                }
+            ],
+            'payment': {
+                'method': 'CASH',
+                'amount_paid': 99.99
+            }
+        }
+
+        sale_response = self.client.post(
+            '/api/v1/retail/sales/',
+            data=json.dumps(sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert sale_response.status_code == status.HTTP_201_CREATED
+
+        # Get customer purchase history
+        history_response = self.client.get(
+            f'/api/v1/retail/customers/{customer_data["id"]}/history/',
+            **self.tenant_auth
+        )
+
+        assert history_response.status_code == status.HTTP_200_OK
+        history_data = history_response.json()
+
+        assert 'purchases' in history_data
+        assert 'total_spent' in history_data
+        assert 'loyalty_points' in history_data
+
+        # Step 2: Customer loyalty program
+        loyalty_data = {
+            'points_earned': 100,
+            'notes': 'Purchase bonus'
+        }
+
+        loyalty_response = self.client.post(
+            f'/api/v1/retail/customers/{customer_data["id"]}/loyalty/',
+            data=json.dumps(loyalty_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert loyalty_response.status_code == status.HTTP_200_OK
+
+    def test_discount_and_promotion_management(self):
+        """Test discount and promotion management."""
+        # Create promotion
+        promotion_data = {
+            'name': 'New Year Sale',
+            'type': 'PERCENTAGE',
+            'value': 20,
+            'start_date': (datetime.now() - timedelta(days=1)).isoformat(),
+            'end_date': (datetime.now() + timedelta(days=30)).isoformat(),
+            'applicable_products': ['product-001', 'product-002'],
+            'minimum_purchase': 100,
+            'usage_limit': 100
+        }
+
+        promotion_response = self.client.post(
+            '/api/v1/retail/promotions/',
+            data=json.dumps(promotion_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert promotion_response.status_code == status.HTTP_201_CREATED
+        created_promotion = promotion_response.json()
+
+        # Test promotion application in sale
+        sale_with_promotion = {
+            'customer': self.customer_data,
+            'items': [
+                {
+                    'product_id': 'product-001',
+                    'sku': 'TEST-001',
+                    'quantity': 2,
+                    'unit_price': 100.00
+                }
+            ],
+            'promotion_code': created_promotion['code'],
+            'payment': {
+                'method': 'CARD',
+                'amount_paid': 160.00  # 20% discount on 200
+            }
+        }
+
+        sale_response = self.client.post(
+            '/api/v1/retail/sales/',
+            data=json.dumps(sale_with_promotion),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert sale_response.status_code == status.HTTP_201_CREATED
+        sale_data = sale_response.json()
+
+        # Verify discount was applied
+        assert 'discount_amount' in sale_data['totals']
+        assert sale_data['totals']['discount_amount'] == 40.00
+
+    def test_return_and_refund_operations(self):
+        """Test return and refund operations."""
+        # Create a sale first
+        sale_data = {
+            'customer': self.customer_data,
+            'items': [
+                {
+                    'product_id': 'product-001',
+                    'sku': 'TEST-001',
+                    'quantity': 2,
+                    'unit_price': 100.00
+                }
+            ],
+            'payment': {
+                'method': 'CARD',
+                'amount_paid': 200.00
+            }
+        }
+
+        sale_response = self.client.post(
+            '/api/v1/retail/sales/',
+            data=json.dumps(sale_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert sale_response.status_code == status.HTTP_201_CREATED
+        created_sale = sale_response.json()
+
+        # Process return
+        return_data = {
+            'sale_id': created_sale['id'],
+            'items': [
+                {
+                    'product_id': 'product-001',
+                    'quantity': 1,
+                    'reason': 'Defective product',
+                    'condition': 'DAMAGED'
+                }
+            ],
+            'refund_method': 'ORIGINAL',
+            'notes': 'Customer reported defective item'
+        }
+
+        return_response = self.client.post(
+            '/api/v1/retail/returns/',
+            data=json.dumps(return_data),
+            content_type='application/json',
+            **self.tenant_auth
+        )
+
+        assert return_response.status_code == status.HTTP_201_CREATED
+        return_data = return_response.json()
+
+        # Verify inventory was updated (returned to stock)
+        # Verify refund was processed
+        assert 'refund_amount' in return_data
+        assert return_data['refund_amount'] == 100.00
+
+    def test_retail_analytics_and_reporting(self):
+        """Test retail analytics and reporting."""
+        # Generate some test data first
+        # This would involve creating multiple products and sales
+
+        # Test sales analytics
+        analytics_response = self.client.get(
+            '/api/v1/retail/analytics/',
+            data={
+                'period': 'monthly',
+                'year': 2024,
+                'month': 1
+            },
+            **self.tenant_auth
+        )
+
+        assert analytics_response.status_code == status.HTTP_200_OK
+        analytics_data = analytics_response.json()
+
+        assert 'revenue' in analytics_data
+        assert 'profit' in analytics_data
+        assert 'top_products' in analytics_data
+        assert 'customer_metrics' in analytics_data
+
+        # Test product performance
+        performance_response = self.client.get(
+            '/api/v1/retail/reports/product-performance/',
+            **self.tenant_auth
+        )
+
+        assert performance_response.status_code == status.HTTP_200_OK
+        performance_data = performance_response.json()
+
+        assert 'products' in performance_data
+        assert 'best_sellers' in performance_data
+        assert 'low_performers' in performance_data

backend/tests/integration/test_subscription_management.py

@@ -0,0 +1,390 @@
+"""
+Integration test for subscription management.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+from datetime import datetime, timedelta
+
+
+class SubscriptionManagementIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer super_admin_token'}
+
+        # Tenant admin authentication header
+        self.tenant_admin_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant_admin_token'}
+
+        # Test subscription data
+        self.subscription_data = {
+            'plan': 'GROWTH',
+            'pricing_model': 'SUBSCRIPTION',
+            'billing_cycle': 'MONTHLY',
+            'payment_method': {
+                'type': 'CARD',
+                'card_last4': '4242',
+                'expiry_month': 12,
+                'expiry_year': 2025,
+                'brand': 'visa'
+            },
+            'modules': ['retail', 'inventory'],
+            'trial_days': 14
+        }
+
+    def test_subscription_lifecycle_management(self):
+        """Test complete subscription lifecycle from trial to cancellation."""
+        # Step 1: Create subscription with trial (should fail before implementation)
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_data = create_response.json()
+
+        # Verify subscription structure
+        assert 'id' in subscription_data
+        assert subscription_data['plan'] == self.subscription_data['plan']
+        assert subscription_data['status'] == 'TRIAL'
+        assert subscription_data['billing_cycle'] == self.subscription_data['billing_cycle']
+
+        # Verify billing period
+        assert 'current_period_start' in subscription_data
+        assert 'current_period_end' in subscription_data
+        assert 'trial_end' in subscription_data
+
+        # Step 2: Test subscription upgrades during trial
+        upgrade_data = {
+            'plan': 'PRO',
+            'reason': 'Business growth requires more features'
+        }
+
+        upgrade_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_data["id"]}/upgrade/',
+            data=json.dumps(upgrade_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert upgrade_response.status_code == status.HTTP_200_OK
+        upgraded_data = upgrade_response.json()
+
+        assert upgraded_data['plan'] == 'PRO'
+        assert upgraded_data['status'] == 'TRIAL'  # Still in trial period
+
+        # Step 3: Simulate trial end and activation
+        # In real implementation, this would be handled by a background job
+        activate_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_data["id"]}/activate/',
+            data=json.dumps({}),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert activate_response.status_code == status.HTTP_200_OK
+        activated_data = activate_response.json()
+
+        assert activated_data['status'] == 'ACTIVE'
+        assert activated_data['plan'] == 'PRO'
+
+        # Step 4: Test subscription usage tracking
+        usage_response = self.client.get(
+            f'/api/v1/subscriptions/{subscription_data["id"]}/usage/',
+            **self.tenant_admin_auth
+        )
+
+        assert usage_response.status_code == status.HTTP_200_OK
+        usage_data = usage_response.json()
+
+        assert 'usage' in usage_data
+        assert 'limits' in usage_data
+        assert 'users_count' in usage_data['usage']
+        assert 'storage_used' in usage_data['usage']
+
+        # Step 5: Test subscription downgrade
+        downgrade_data = {
+            'plan': 'GROWTH',
+            'effective_date': (datetime.now() + timedelta(days=30)).isoformat()
+        }
+
+        downgrade_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_data["id"]}/downgrade/',
+            data=json.dumps(downgrade_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert downgrade_response.status_code == status.HTTP_200_OK
+        downgraded_data = downgrade_response.json()
+
+        assert downgraded_data['pending_plan'] == 'GROWTH'
+        assert downgraded_data['plan_change_effective_date'] == downgrade_data['effective_date']
+
+        # Step 6: Test subscription cancellation
+        cancel_data = {
+            'reason': 'Business closure',
+            'feedback': 'Closing down operations',
+            'immediate': False
+        }
+
+        cancel_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_data["id"]}/cancel/',
+            data=json.dumps(cancel_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert cancel_response.status_code == status.HTTP_200_OK
+        cancelled_data = cancel_response.json()
+
+        assert cancelled_data['status'] == 'ACTIVE'  # Still active until end of period
+        assert cancelled_data['cancel_at_period_end'] is True
+
+    def test_subscription_billing_and_payments(self):
+        """Test subscription billing and payment processing."""
+        # Create subscription
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Test billing history
+        billing_response = self.client.get(
+            f'/api/v1/subscriptions/{subscription_id}/billing/',
+            **self.tenant_admin_auth
+        )
+
+        assert billing_response.status_code == status.HTTP_200_OK
+        billing_data = billing_response.json()
+
+        assert 'invoices' in billing_data
+        assert 'payments' in billing_data
+        assert 'upcoming_invoice' in billing_data
+
+        # Test payment method management
+        payment_method_data = {
+            'type': 'CARD',
+            'card_number': '4242424242424242',
+            'expiry_month': 12,
+            'expiry_year': 2025,
+            'cvv': '123',
+            'cardholder_name': 'Test User'
+        }
+
+        add_payment_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_id}/payment-methods/',
+            data=json.dumps(payment_method_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert add_payment_response.status_code == status.HTTP_201_CREATED
+
+    def test_subscription_plan_changes_validation(self):
+        """Test validation of subscription plan changes."""
+        # Create subscription
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Test invalid plan upgrade
+        invalid_upgrade_data = {
+            'plan': 'INVALID_PLAN'
+        }
+
+        invalid_upgrade_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_id}/upgrade/',
+            data=json.dumps(invalid_upgrade_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert invalid_upgrade_response.status_code == status.HTTP_400_BAD_REQUEST
+
+        # Test downgrade to same plan
+        same_plan_data = {
+            'plan': self.subscription_data['plan']
+        }
+
+        same_plan_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_id}/downgrade/',
+            data=json.dumps(same_plan_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert same_plan_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_subscription_module_management(self):
+        """Test subscription module add-ons and management."""
+        # Create base subscription
+        base_subscription = self.subscription_data.copy()
+        base_subscription['modules'] = ['retail']
+
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(base_subscription),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Add module
+        add_module_data = {
+            'module': 'inventory',
+            'pricing_model': 'PER_MODULE',
+            'billing_cycle': 'MONTHLY'
+        }
+
+        add_module_response = self.client.post(
+            f'/api/v1/subscriptions/{subscription_id}/modules/',
+            data=json.dumps(add_module_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert add_module_response.status_code == status.HTTP_200_OK
+
+        # Remove module
+        remove_module_response = self.client.delete(
+            f'/api/v1/subscriptions/{subscription_id}/modules/inventory/',
+            **self.tenant_admin_auth
+        )
+
+        assert remove_module_response.status_code == status.HTTP_200_OK
+
+    def test_subscription_usage_limits(self):
+        """Test subscription usage limits and overage handling."""
+        # Create subscription with specific limits
+        limited_subscription = self.subscription_data.copy()
+        limited_subscription['usage_limits'] = {
+            'users': 5,
+            'storage_gb': 10,
+            'api_calls_per_month': 10000
+        }
+
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(limited_subscription),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Check usage limits
+        limits_response = self.client.get(
+            f'/api/v1/subscriptions/{subscription_id}/limits/',
+            **self.tenant_admin_auth
+        )
+
+        assert limits_response.status_code == status.HTTP_200_OK
+        limits_data = limits_response.json()
+
+        assert 'limits' in limits_data
+        assert 'current_usage' in limits_data
+        assert 'overage_charges' in limits_data
+
+    def test_subscription_discounts_and_promotions(self):
+        """Test subscription discounts and promotional codes."""
+        # Create subscription with promo code
+        promo_subscription = self.subscription_data.copy()
+        promo_subscription['promo_code'] = 'WELCOME20'
+
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(promo_subscription),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_data = create_response.json()
+
+        # Check discount was applied
+        assert 'discount' in subscription_data
+        assert subscription_data['promo_code'] == 'WELCOME20'
+
+    def test_subscription_notifications_and_reminders(self):
+        """Test subscription notifications and renewal reminders."""
+        # Create subscription
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Test notification settings
+        notification_settings = {
+            'email_notifications': True,
+            'renewal_reminders': True,
+            'usage_alerts': True,
+            'billing_notifications': True
+        }
+
+        settings_response = self.client.put(
+            f'/api/v1/subscriptions/{subscription_id}/notifications/',
+            data=json.dumps(notification_settings),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert settings_response.status_code == status.HTTP_200_OK
+
+    def test_subscription_audit_trail(self):
+        """Test subscription changes audit trail."""
+        # Create subscription
+        create_response = self.client.post(
+            '/api/v1/subscriptions/',
+            data=json.dumps(self.subscription_data),
+            content_type='application/json',
+            **self.tenant_admin_auth
+        )
+
+        assert create_response.status_code == status.HTTP_201_CREATED
+        subscription_id = create_response.json()['id']
+
+        # Get audit trail
+        audit_response = self.client.get(
+            f'/api/v1/subscriptions/{subscription_id}/audit/',
+            **self.admin_auth
+        )
+
+        assert audit_response.status_code == status.HTTP_200_OK
+        audit_data = audit_response.json()
+
+        assert 'changes' in audit_data
+        assert isinstance(audit_data['changes'], list)
+        assert len(audit_data['changes']) > 0
+
+        # First change should be subscription creation
+        first_change = audit_data['changes'][0]
+        assert first_change['action'] == 'CREATE'
+        assert first_change['user_id'] is not None

backend/tests/integration/test_tenant_isolation.py

@@ -0,0 +1,404 @@
+"""
+Integration test for multi-tenant data isolation.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class TenantIsolationIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Super admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer super_admin_token'}
+
+        # Tenant 1 authentication header
+        self.tenant1_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant1_admin_token'}
+
+        # Tenant 2 authentication header
+        self.tenant2_auth = {'HTTP_AUTHORIZATION': 'Bearer tenant2_admin_token'}
+
+        # Test data for different tenants
+        self.tenant1_user_data = {
+            'email': 'user1@tenant1.com',
+            'name': 'User One',
+            'role': 'MANAGER',
+            'department': 'Sales'
+        }
+
+        self.tenant2_user_data = {
+            'email': 'user1@tenant2.com',
+            'name': 'User One Duplicate',
+            'role': 'MANAGER',
+            'department': 'Marketing'
+        }
+
+        self.tenant1_product_data = {
+            'sku': 'PROD-001',
+            'name': 'Product A',
+            'category': 'ELECTRONICS',
+            'price': 999.99
+        }
+
+        self.tenant2_product_data = {
+            'sku': 'PROD-001',  # Same SKU as tenant1
+            'name': 'Product A Different',
+            'category': 'ELECTRONICS',
+            'price': 899.99
+        }
+
+    def test_user_data_isolation(self):
+        """Test that user data is properly isolated between tenants."""
+        # Step 1: Create users in different tenants with same email structure
+        tenant1_user_response = self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant1_user_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_user_response.status_code == status.HTTP_201_CREATED
+        tenant1_user = tenant1_user_response.json()
+
+        tenant2_user_response = self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant2_user_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_user_response.status_code == status.HTTP_201_CREATED
+        tenant2_user = tenant2_user_response.json()
+
+        # Step 2: Verify tenant isolation - each tenant should only see their own users
+        tenant1_users_response = self.client.get(
+            '/api/v1/users/',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_users_response.status_code == status.HTTP_200_OK
+        tenant1_users = tenant1_users_response.json()['users']
+
+        # Should only see users from tenant1
+        assert len(tenant1_users) == 1
+        assert tenant1_users[0]['email'] == self.tenant1_user_data['email']
+        assert tenant1_users[0]['tenant_id'] == tenant1_user['tenant_id']
+
+        tenant2_users_response = self.client.get(
+            '/api/v1/users/',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_users_response.status_code == status.HTTP_200_OK
+        tenant2_users = tenant2_users_response.json()['users']
+
+        # Should only see users from tenant2
+        assert len(tenant2_users) == 1
+        assert tenant2_users[0]['email'] == self.tenant2_user_data['email']
+        assert tenant2_users[0]['tenant_id'] == tenant2_user['tenant_id']
+
+        # Step 3: Super admin should see all users
+        admin_users_response = self.client.get(
+            '/api/v1/users/',
+            **self.admin_auth
+        )
+
+        assert admin_users_response.status_code == status.HTTP_200_OK
+        admin_users = admin_users_response.json()['users']
+
+        # Should see users from both tenants
+        assert len(admin_users) >= 2
+        user_emails = [user['email'] for user in admin_users]
+        assert self.tenant1_user_data['email'] in user_emails
+        assert self.tenant2_user_data['email'] in user_emails
+
+    def test_product_data_isolation(self):
+        """Test that product data is properly isolated between tenants."""
+        # Step 1: Create products with same SKU in different tenants
+        tenant1_product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(self.tenant1_product_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_product_response.status_code == status.HTTP_201_CREATED
+        tenant1_product = tenant1_product_response.json()
+
+        tenant2_product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(self.tenant2_product_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_product_response.status_code == status.HTTP_201_CREATED
+        tenant2_product = tenant2_product_response.json()
+
+        # Step 2: Verify SKU isolation - same SKU allowed in different tenants
+        assert tenant1_product['sku'] == tenant2_product['sku']
+        assert tenant1_product['id'] != tenant2_product['id']
+        assert tenant1_product['tenant_id'] != tenant2_product['tenant_id']
+
+        # Step 3: Test product retrieval isolation
+        tenant1_products_response = self.client.get(
+            '/api/v1/retail/products/',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_products_response.status_code == status.HTTP_200_OK
+        tenant1_products = tenant1_products_response.json()['products']
+
+        # Should only see products from tenant1
+        assert len(tenant1_products) == 1
+        assert tenant1_products[0]['name'] == self.tenant1_product_data['name']
+        assert tenant1_products[0]['tenant_id'] == tenant1_product['tenant_id']
+
+        tenant2_products_response = self.client.get(
+            '/api/v1/retail/products/',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_products_response.status_code == status.HTTP_200_OK
+        tenant2_products = tenant2_products_response.json()['products']
+
+        # Should only see products from tenant2
+        assert len(tenant2_products) == 1
+        assert tenant2_products[0]['name'] == self.tenant2_product_data['name']
+        assert tenant2_products[0]['tenant_id'] == tenant2_product['tenant_id']
+
+    def test_healthcare_data_isolation(self):
+        """Test that healthcare patient data is properly isolated."""
+        # Patient data for different tenants
+        tenant1_patient_data = {
+            'ic_number': '900101-10-1234',
+            'name': 'Ahmad bin Hassan',
+            'gender': 'MALE',
+            'date_of_birth': '1990-01-01'
+        }
+
+        tenant2_patient_data = {
+            'ic_number': '900101-10-1234',  # Same IC number
+            'name': 'Ahmad bin Ali',  # Different name
+            'gender': 'MALE',
+            'date_of_birth': '1990-01-01'
+        }
+
+        # Create patients in different tenants
+        tenant1_patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(tenant1_patient_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_patient_response.status_code == status.HTTP_201_CREATED
+        tenant1_patient = tenant1_patient_response.json()
+
+        tenant2_patient_response = self.client.post(
+            '/api/v1/healthcare/patients/',
+            data=json.dumps(tenant2_patient_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_patient_response.status_code == status.HTTP_201_CREATED
+        tenant2_patient = tenant2_patient_response.json()
+
+        # Verify same IC number allowed in different tenants (healthcare compliance)
+        assert tenant1_patient['ic_number'] == tenant2_patient['ic_number']
+        assert tenant1_patient['id'] != tenant2_patient['id']
+
+        # Test patient data isolation
+        tenant1_patients_response = self.client.get(
+            '/api/v1/healthcare/patients/',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_patients_response.status_code == status.HTTP_200_OK
+        tenant1_patients = tenant1_patients_response.json()['patients']
+
+        # Should only see patients from tenant1
+        assert len(tenant1_patients) == 1
+        assert tenant1_patients[0]['name'] == tenant1_patient_data['name']
+
+    def test_cross_tenant_access_prevention(self):
+        """Test that cross-tenant access is properly prevented."""
+        # Step 1: Create a user in tenant1
+        tenant1_user_response = self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant1_user_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_user_response.status_code == status.HTTP_201_CREATED
+        created_user = tenant1_user_response.json()
+        user_id = created_user['id']
+
+        # Step 2: Try to access tenant1 user from tenant2 (should fail)
+        tenant2_access_response = self.client.get(
+            f'/api/v1/users/{user_id}/',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_access_response.status_code == status.HTTP_404_NOT_FOUND
+
+        # Step 3: Try to modify tenant1 user from tenant2 (should fail)
+        modify_data = {'name': 'Hacked Name'}
+
+        tenant2_modify_response = self.client.put(
+            f'/api/v1/users/{user_id}/',
+            data=json.dumps(modify_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        assert tenant2_modify_response.status_code == status.HTTP_404_NOT_FOUND
+
+        # Step 4: Verify user data is unchanged
+        verify_response = self.client.get(
+            f'/api/v1/users/{user_id}/',
+            **self.tenant1_auth
+        )
+
+        assert verify_response.status_code == status.HTTP_200_OK
+        verified_user = verify_response.json()
+        assert verified_user['name'] == self.tenant1_user_data['name']
+
+    def test_database_row_level_security(self):
+        """Test that database row-level security is working."""
+        # This test verifies that data isolation is enforced at the database level
+
+        # Create test data in both tenants
+        self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant1_user_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant2_user_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        # Test direct database queries would be isolated
+        # This is more of an integration test that would require actual database setup
+        pass
+
+    def test_file_storage_isolation(self):
+        """Test that file storage is properly isolated between tenants."""
+        # Upload files for different tenants
+        # This would test file storage isolation mechanisms
+        pass
+
+    def test_cache_isolation(self):
+        """Test that cache keys are properly isolated between tenants."""
+        # Test that cache keys include tenant information
+        # This ensures cache data doesn't leak between tenants
+        pass
+
+    def test_tenant_context_propagation(self):
+        """Test that tenant context is properly propagated through the system."""
+        # Create a user and verify tenant context is maintained across operations
+        user_response = self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant1_user_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert user_response.status_code == status.HTTP_201_CREATED
+        created_user = user_response.json()
+
+        # Verify tenant ID is consistently set
+        assert 'tenant_id' in created_user
+        tenant_id = created_user['tenant_id']
+
+        # Create a product and verify same tenant context
+        product_response = self.client.post(
+            '/api/v1/retail/products/',
+            data=json.dumps(self.tenant1_product_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        assert product_response.status_code == status.HTTP_201_CREATED
+        created_product = product_response.json()
+
+        assert created_product['tenant_id'] == tenant_id
+
+    def test_tenant_configuration_isolation(self):
+        """Test that tenant configurations are properly isolated."""
+        # Set tenant-specific configurations
+        tenant1_config = {
+            'timezone': 'Asia/Kuala_Lumpur',
+            'currency': 'MYR',
+            'date_format': 'DD/MM/YYYY'
+        }
+
+        tenant2_config = {
+            'timezone': 'Asia/Singapore',
+            'currency': 'SGD',
+            'date_format': 'MM/DD/YYYY'
+        }
+
+        # Apply configurations (would need actual config endpoints)
+        # Verify configurations don't interfere
+        pass
+
+    def test_tenant_performance_isolation(self):
+        """Test that one tenant's performance doesn't affect others."""
+        # This would test resource limits and performance isolation
+        pass
+
+    def test_audit_log_tenant_isolation(self):
+        """Test that audit logs are properly isolated by tenant."""
+        # Perform actions in different tenants
+        self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant1_user_data),
+            content_type='application/json',
+            **self.tenant1_auth
+        )
+
+        self.client.post(
+            '/api/v1/users/',
+            data=json.dumps(self.tenant2_user_data),
+            content_type='application/json',
+            **self.tenant2_auth
+        )
+
+        # Check that each tenant only sees their own audit logs
+        tenant1_audit_response = self.client.get(
+            '/api/v1/audit/logs/',
+            **self.tenant1_auth
+        )
+
+        assert tenant1_audit_response.status_code == status.HTTP_200_OK
+        tenant1_logs = tenant1_audit_response.json()['logs']
+
+        # Should only see logs from tenant1 operations
+        for log in tenant1_logs:
+            assert log['tenant_id'] is not None
+
+        # Super admin should see all logs
+        admin_audit_response = self.client.get(
+            '/api/v1/audit/logs/',
+            **self.admin_auth
+        )
+
+        assert admin_audit_response.status_code == status.HTTP_200_OK
+        admin_logs = admin_audit_response.json()['logs']
+
+        # Should see logs from both tenants
+        assert len(admin_logs) >= len(tenant1_logs)

backend/tests/integration/test_tenant_registration.py

@@ -0,0 +1,322 @@
+"""
+Integration test for tenant registration flow.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+
+
+class TenantRegistrationIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Super admin authentication header
+        self.admin_auth = {'HTTP_AUTHORIZATION': 'Bearer super_admin_token'}
+
+        # Test tenant data
+        self.tenant_data = {
+            'name': 'Test Healthcare Sdn Bhd',
+            'email': 'info@testhealthcare.com',
+            'phone': '+60312345678',
+            'address': {
+                'street': '123 Medical Street',
+                'city': 'Kuala Lumpur',
+                'state': 'Wilayah Persekutuan',
+                'postal_code': '50400',
+                'country': 'Malaysia'
+            },
+            'business_type': 'HEALTHCARE',
+            'subscription_plan': 'GROWTH',
+            'pricing_model': 'SUBSCRIPTION',
+            'admin_user': {
+                'name': 'Dr. Sarah Johnson',
+                'email': 'sarah.johnson@testhealthcare.com',
+                'password': 'SecurePassword123!',
+                'role': 'TENANT_ADMIN',
+                'phone': '+60123456789'
+            }
+        }
+
+    def test_complete_tenant_registration_flow(self):
+        """Test complete tenant registration from creation to admin setup."""
+        # Step 1: Create tenant (should fail before implementation)
+        tenant_response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert tenant_response.status_code == status.HTTP_201_CREATED
+        tenant_data = tenant_response.json()
+
+        # Verify tenant structure
+        assert 'id' in tenant_data
+        assert tenant_data['name'] == self.tenant_data['name']
+        assert tenant_data['email'] == self.tenant_data['email']
+        assert tenant_data['business_type'] == self.tenant_data['business_type']
+        assert tenant_data['status'] == 'PENDING'
+
+        # Step 2: Verify tenant admin user was created
+        # First, authenticate as super admin to get user list
+        users_response = self.client.get(
+            '/api/v1/users/',
+            **self.admin_auth
+        )
+
+        assert users_response.status_code == status.HTTP_200_OK
+        users_data = users_response.json()
+
+        # Find the newly created admin user
+        admin_user = None
+        for user in users_data['users']:
+            if user['email'] == self.tenant_data['admin_user']['email']:
+                admin_user = user
+                break
+
+        assert admin_user is not None
+        assert admin_user['name'] == self.tenant_data['admin_user']['name']
+        assert admin_user['role'] == 'TENANT_ADMIN'
+        assert admin_user['tenant_id'] == tenant_data['id']
+
+        # Step 3: Verify subscription was created for tenant
+        subscription_response = self.client.get(
+            '/api/v1/subscriptions/',
+            data={'tenant_id': tenant_data['id']},
+            **self.admin_auth
+        )
+
+        assert subscription_response.status_code == status.HTTP_200_OK
+        subscriptions_data = subscription_response.json()
+
+        assert len(subscriptions_data['subscriptions']) == 1
+        subscription = subscriptions_data['subscriptions'][0]
+        assert subscription['tenant_id'] == tenant_data['id']
+        assert subscription['plan'] == self.tenant_data['subscription_plan']
+        assert subscription['status'] == 'TRIAL'
+
+        # Step 4: Test tenant admin authentication
+        # Login as tenant admin
+        login_data = {
+            'email': self.tenant_data['admin_user']['email'],
+            'password': self.tenant_data['admin_user']['password']
+        }
+
+        auth_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps(login_data),
+            content_type='application/json'
+        )
+
+        assert auth_response.status_code == status.HTTP_200_OK
+        auth_data = auth_response.json()
+
+        assert 'access_token' in auth_data
+        assert 'refresh_token' in auth_data
+        assert 'user' in auth_data
+
+        # Verify user info in token
+        user_info = auth_data['user']
+        assert user_info['email'] == self.tenant_data['admin_user']['email']
+        assert user_info['tenant_id'] == tenant_data['id']
+
+        # Step 5: Test tenant admin can access their tenant data
+        tenant_admin_auth = {'HTTP_AUTHORIZATION': f'Bearer {auth_data["access_token"]}'}
+
+        tenant_own_response = self.client.get(
+            '/api/v1/tenants/',
+            **tenant_admin_auth
+        )
+
+        assert tenant_own_response.status_code == status.HTTP_200_OK
+        tenant_own_data = tenant_own_response.json()
+
+        # Should only see their own tenant
+        assert len(tenant_own_data['tenants']) == 1
+        assert tenant_own_data['tenants'][0]['id'] == tenant_data['id']
+
+        # Step 6: Test tenant isolation - cannot see other tenants
+        # Create another tenant as super admin
+        other_tenant_data = self.tenant_data.copy()
+        other_tenant_data['name'] = 'Other Healthcare Sdn Bhd'
+        other_tenant_data['email'] = 'info@otherhealthcare.com'
+        other_tenant_data['admin_user']['email'] = 'admin@otherhealthcare.com'
+
+        other_tenant_response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(other_tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert other_tenant_response.status_code == status.HTTP_201_CREATED
+
+        # First tenant admin should still only see their own tenant
+        tenant_still_own_response = self.client.get(
+            '/api/v1/tenants/',
+            **tenant_admin_auth
+        )
+
+        assert tenant_still_own_response.status_code == status.HTTP_200_OK
+        tenant_still_own_data = tenant_still_own_response.json()
+
+        # Should still only see their own tenant
+        assert len(tenant_still_own_data['tenants']) == 1
+        assert tenant_still_own_data['tenants'][0]['id'] == tenant_data['id']
+
+    def test_tenant_registration_invalid_business_type(self):
+        """Test tenant registration with invalid business type."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['business_type'] = 'INVALID_TYPE'
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_tenant_registration_missing_admin_user(self):
+        """Test tenant registration without admin user data."""
+        invalid_data = self.tenant_data.copy()
+        del invalid_data['admin_user']
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_tenant_registration_duplicate_email(self):
+        """Test tenant registration with duplicate email."""
+        # Create first tenant
+        first_response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert first_response.status_code == status.HTTP_201_CREATED
+
+        # Try to create second tenant with same email
+        second_response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(self.tenant_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert second_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_tenant_registration_unauthorized(self):
+        """Test tenant registration without admin authentication."""
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(self.tenant_data),
+            content_type='application/json'
+        )
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_tenant_registration_weak_admin_password(self):
+        """Test tenant registration with weak admin password."""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['admin_user']['password'] = '123'
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(invalid_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_tenant_registration_with_modules_configuration(self):
+        """Test tenant registration with specific modules configuration."""
+        modules_data = self.tenant_data.copy()
+        modules_data['modules'] = ['healthcare', 'appointments', 'billing']
+        modules_data['modules_config'] = {
+            'healthcare': {
+                'features': ['patient_management', 'appointment_scheduling', 'medical_records'],
+                'settings': {
+                    'enable_telemedicine': True,
+                    'appointment_reminders': True
+                }
+            }
+        }
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(modules_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            tenant_data = response.json()
+            # Should have modules configuration
+            assert 'modules' in tenant_data
+            assert 'modules_config' in tenant_data
+
+    def test_tenant_registration_with_branding(self):
+        """Test tenant registration with branding information."""
+        branding_data = self.tenant_data.copy()
+        branding_data['branding'] = {
+            'logo_url': 'https://example.com/logo.png',
+            'primary_color': '#2563eb',
+            'secondary_color': '#64748b',
+            'company_website': 'https://testhealthcare.com',
+            'social_media': {
+                'facebook': 'testhealthcare',
+                'instagram': 'testhealthcare_my'
+            }
+        }
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(branding_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            tenant_data = response.json()
+            # Should have branding information
+            assert 'branding' in tenant_data
+            assert tenant_data['branding']['primary_color'] == '#2563eb'
+
+    def test_tenant_registration_domain_setup(self):
+        """Test tenant registration with custom domain setup."""
+        domain_data = self.tenant_data.copy()
+        domain_data['domain'] = 'portal.testhealthcare.com'
+        domain_data['settings'] = {
+            'custom_domain_enabled': True,
+            'ssl_enabled': True,
+            'email_domain': 'testhealthcare.com'
+        }
+
+        response = self.client.post(
+            '/api/v1/tenants/',
+            data=json.dumps(domain_data),
+            content_type='application/json',
+            **self.admin_auth
+        )
+
+        if response.status_code == status.HTTP_201_CREATED:
+            tenant_data = response.json()
+            # Should have domain configuration
+            assert 'domain' in tenant_data
+            assert 'settings' in tenant_data
+            assert tenant_data['domain'] == 'portal.testhealthcare.com'

backend/tests/integration/test_user_authentication.py

@@ -0,0 +1,391 @@
+"""
+Integration test for user authentication flow.
+This test MUST fail before implementation.
+"""
+
+import pytest
+from django.test import TestCase
+from django.urls import reverse
+from rest_framework.test import APIClient
+from rest_framework import status
+import json
+import time
+
+
+class UserAuthenticationIntegrationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+
+        # Test user credentials
+        self.test_user = {
+            'email': 'test.user@example.com',
+            'password': 'SecurePassword123!',
+            'name': 'Test User',
+            'role': 'TENANT_ADMIN'
+        }
+
+    def test_complete_authentication_flow(self):
+        """Test complete authentication flow from login to logout."""
+        # Step 1: User login (should fail before implementation)
+        login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': self.test_user['password']
+            }),
+            content_type='application/json'
+        )
+
+        assert login_response.status_code == status.HTTP_200_OK
+        login_data = login_response.json()
+
+        # Verify token structure
+        assert 'access_token' in login_data
+        assert 'refresh_token' in login_data
+        assert 'user' in login_data
+        assert 'expires_in' in login_data
+
+        access_token = login_data['access_token']
+        refresh_token = login_data['refresh_token']
+        user_info = login_data['user']
+
+        # Verify user information
+        assert user_info['email'] == self.test_user['email']
+        assert user_info['name'] == self.test_user['name']
+        assert user_info['role'] == self.test_user['role']
+        assert 'tenant_id' in user_info
+
+        # Step 2: Use access token for authenticated requests
+        auth_header = {'HTTP_AUTHORIZATION': f'Bearer {access_token}'}
+
+        # Test accessing protected resource
+        protected_response = self.client.get(
+            '/api/v1/users/',
+            **auth_header
+        )
+
+        assert protected_response.status_code == status.HTTP_200_OK
+
+        # Step 3: Test token refresh
+        refresh_response = self.client.post(
+            '/api/v1/auth/refresh/',
+            data=json.dumps({
+                'refresh_token': refresh_token
+            }),
+            content_type='application/json'
+        )
+
+        assert refresh_response.status_code == status.HTTP_200_OK
+        refresh_data = refresh_response.json()
+
+        # Verify new tokens
+        assert 'access_token' in refresh_data
+        assert 'refresh_token' in refresh_data
+
+        # New access token should be different (rotation)
+        new_access_token = refresh_data['access_token']
+        assert new_access_token != access_token
+
+        # New refresh token should also be different (rotation)
+        new_refresh_token = refresh_data['refresh_token']
+        assert new_refresh_token != refresh_token
+
+        # Step 4: Test new access token works
+        new_auth_header = {'HTTP_AUTHORIZATION': f'Bearer {new_access_token}'}
+
+        new_protected_response = self.client.get(
+            '/api/v1/users/',
+            **new_auth_header
+        )
+
+        assert new_protected_response.status_code == status.HTTP_200_OK
+
+        # Step 5: Test old refresh token is invalidated
+        old_refresh_response = self.client.post(
+            '/api/v1/auth/refresh/',
+            data=json.dumps({
+                'refresh_token': refresh_token  # Old token
+            }),
+            content_type='application/json'
+        )
+
+        assert old_refresh_response.status_code == status.HTTP_401_UNAUTHORIZED
+
+        # Step 6: Test logout/blacklist tokens
+        logout_response = self.client.post(
+            '/api/v1/auth/logout/',
+            **new_auth_header
+        )
+
+        assert logout_response.status_code == status.HTTP_200_OK
+        logout_data = logout_response.json()
+
+        assert 'message' in logout_data
+        assert logout_data['message'] == 'Successfully logged out'
+
+        # Step 7: Test token is blacklisted (cannot be used after logout)
+        blacklisted_response = self.client.get(
+            '/api/v1/users/',
+            **new_auth_header
+        )
+
+        assert blacklisted_response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    def test_multi_factor_authentication_flow(self):
+        """Test multi-factor authentication flow."""
+        # Step 1: Initial login with MFA enabled user
+        mfa_login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': 'mfa.user@example.com',
+                'password': 'SecurePassword123!'
+            }),
+            content_type='application/json'
+        )
+
+        # Should return MFA challenge instead of full token
+        assert mfa_login_response.status_code == status.HTTP_200_OK
+        mfa_data = mfa_login_response.json()
+
+        assert 'mfa_required' in mfa_data
+        assert mfa_data['mfa_required'] is True
+        assert 'mfa_methods' in mfa_data
+        assert 'temp_token' in mfa_data
+
+        # Step 2: Complete MFA with TOTP
+        mfa_verify_response = self.client.post(
+            '/api/v1/auth/mfa/verify/',
+            data=json.dumps({
+                'temp_token': mfa_data['temp_token'],
+                'method': 'TOTP',
+                'code': '123456'  # Mock TOTP code
+            }),
+            content_type='application/json'
+        )
+
+        assert mfa_verify_response.status_code == status.HTTP_200_OK
+        mfa_verify_data = mfa_verify_response.json()
+
+        assert 'access_token' in mfa_verify_data
+        assert 'refresh_token' in mfa_verify_data
+
+    def test_authentication_error_scenarios(self):
+        """Test various authentication error scenarios."""
+        # Test invalid credentials
+        invalid_credentials_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': 'wrongpassword'
+            }),
+            content_type='application/json'
+        )
+
+        assert invalid_credentials_response.status_code == status.HTTP_401_UNAUTHORIZED
+
+        # Test missing credentials
+        missing_credentials_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email']
+                # Missing password
+            }),
+            content_type='application/json'
+        )
+
+        assert missing_credentials_response.status_code == status.HTTP_400_BAD_REQUEST
+
+        # Test invalid refresh token
+        invalid_refresh_response = self.client.post(
+            '/api/v1/auth/refresh/',
+            data=json.dumps({
+                'refresh_token': 'invalid_refresh_token'
+            }),
+            content_type='application/json'
+        )
+
+        assert invalid_refresh_response.status_code == status.HTTP_401_UNAUTHORIZED
+
+        # Test missing refresh token
+        missing_refresh_response = self.client.post(
+            '/api/v1/auth/refresh/',
+            data=json.dumps({}),
+            content_type='application/json'
+        )
+
+        assert missing_refresh_response.status_code == status.HTTP_400_BAD_REQUEST
+
+    def test_token_expiry_handling(self):
+        """Test handling of expired tokens."""
+        # This test would need to simulate token expiration
+        # For now, we'll test the structure
+        pass
+
+    def test_concurrent_session_management(self):
+        """Test concurrent session management."""
+        # Login first device
+        device1_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': self.test_user['password']
+            }),
+            content_type='application/json'
+        )
+
+        assert device1_response.status_code == status.HTTP_200_OK
+        device1_token = device1_response.json()['access_token']
+
+        # Login second device
+        device2_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': self.test_user['password']
+            }),
+            content_type='application/json'
+        )
+
+        assert device2_response.status_code == status.HTTP_200_OK
+        device2_token = device2_response.json()['access_token']
+
+        # Both tokens should work (assuming concurrent sessions are allowed)
+        device1_auth = {'HTTP_AUTHORIZATION': f'Bearer {device1_token}'}
+        device2_auth = {'HTTP_AUTHORIZATION': f'Bearer {device2_token}'}
+
+        device1_protected = self.client.get('/api/v1/users/', **device1_auth)
+        device2_protected = self.client.get('/api/v1/users/', **device2_auth)
+
+        assert device1_protected.status_code == status.HTTP_200_OK
+        assert device2_protected.status_code == status.HTTP_200_OK
+
+    def test_permission_based_access_control(self):
+        """Test permission-based access control."""
+        # Login as regular user
+        user_login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': 'regular.user@example.com',
+                'password': 'SecurePassword123!'
+            }),
+            content_type='application/json'
+        )
+
+        assert user_login_response.status_code == status.HTTP_200_OK
+        user_token = user_login_response.json()['access_token']
+        user_auth = {'HTTP_AUTHORIZATION': f'Bearer {user_token}'}
+
+        # Regular user should not be able to access admin-only endpoints
+        admin_endpoint_response = self.client.get('/api/v1/tenants/', **user_auth)
+        assert admin_endpoint_response.status_code == status.HTTP_403_FORBIDDEN
+
+        # But should be able to access user endpoints
+        user_endpoint_response = self.client.get('/api/v1/users/', **user_auth)
+        assert user_endpoint_response.status_code == status.HTTP_200_OK
+
+    def test_tenant_isolation_in_authentication(self):
+        """Test that authentication tokens include tenant isolation."""
+        # Login as tenant admin
+        tenant_admin_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': 'tenant.admin@tenant1.com',
+                'password': 'SecurePassword123!'
+            }),
+            content_type='application/json'
+        )
+
+        assert tenant_admin_response.status_code == status.HTTP_200_OK
+        tenant_admin_data = tenant_admin_response.json()
+
+        # Token should include tenant information
+        assert 'tenant_id' in tenant_admin_data['user']
+        tenant1_id = tenant_admin_data['user']['tenant_id']
+
+        # Login as different tenant admin
+        tenant2_admin_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': 'tenant.admin@tenant2.com',
+                'password': 'SecurePassword123!'
+            }),
+            content_type='application/json'
+        )
+
+        assert tenant2_admin_response.status_code == status.HTTP_200_OK
+        tenant2_admin_data = tenant2_admin_response.json()
+
+        # Should have different tenant ID
+        assert 'tenant_id' in tenant2_admin_data['user']
+        tenant2_id = tenant2_admin_data['user']['tenant_id']
+
+        assert tenant1_id != tenant2_id
+
+    def test_authentication_rate_limiting(self):
+        """Test authentication rate limiting."""
+        # Test multiple failed login attempts
+        for i in range(5):
+            failed_response = self.client.post(
+                '/api/v1/auth/login/',
+                data=json.dumps({
+                    'email': self.test_user['email'],
+                    'password': 'wrongpassword'
+                }),
+                content_type='application/json'
+            )
+
+            # Should still allow attempts but may implement rate limiting
+            assert failed_response.status_code in [status.HTTP_401_UNAUTHORIZED, status.HTTP_429_TOO_MANY_REQUESTS]
+
+    def test_password_change_flow(self):
+        """Test password change flow with authentication."""
+        # Login first
+        login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': self.test_user['password']
+            }),
+            content_type='application/json'
+        )
+
+        assert login_response.status_code == status.HTTP_200_OK
+        access_token = login_response.json()['access_token']
+        auth_header = {'HTTP_AUTHORIZATION': f'Bearer {access_token}'}
+
+        # Change password
+        password_change_response = self.client.post(
+            '/api/v1/auth/change-password/',
+            data=json.dumps({
+                'current_password': self.test_user['password'],
+                'new_password': 'NewSecurePassword456!'
+            }),
+            content_type='application/json',
+            **auth_header
+        )
+
+        assert password_change_response.status_code == status.HTTP_200_OK
+
+        # Test login with new password
+        new_login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': 'NewSecurePassword456!'
+            }),
+            content_type='application/json'
+        )
+
+        assert new_login_response.status_code == status.HTTP_200_OK
+
+        # Test old password no longer works
+        old_login_response = self.client.post(
+            '/api/v1/auth/login/',
+            data=json.dumps({
+                'email': self.test_user['email'],
+                'password': self.test_user['password']
+            }),
+            content_type='application/json'
+        )
+
+        assert old_login_response.status_code == status.HTTP_401_UNAUTHORIZED

backend/tests/load/test_multi_tenant_load.py

@@ -0,0 +1,846 @@
+"""
+Load Testing for Multi-Tenant Scenarios
+
+Comprehensive load testing for:
+- Concurrent tenant operations
+- Database connection pooling under load
+- Schema isolation performance
+- Resource usage optimization
+- Scalability testing
+
+Author: Claude
+"""
+
+import pytest
+import time
+import threading
+import statistics
+import queue
+import random
+from datetime import datetime, timedelta
+from decimal import Decimal
+from django.test import TestCase
+from django.db import connection, connections, transaction
+from django.contrib.auth import get_user_model
+from django.core.management import call_command
+from django.conf import settings
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.core.models.subscription import Subscription
+from backend.src.modules.retail.models.product import Product
+from backend.src.modules.healthcare.models.patient import Patient
+from backend.src.modules.education.models.student import Student
+from backend.src.modules.logistics.models.shipment import Shipment
+from backend.src.modules.beauty.models.client import Client
+
+User = get_user_model()
+
+
+class MultiTenantLoadTest(TestCase):
+    """Load testing for multi-tenant scenarios"""
+
+    def setUp(self):
+        """Set up test environment for load testing"""
+        # Create base tenants for load testing
+        self.tenants = []
+        for i in range(20):
+            tenant = Tenant.objects.create(
+                name=f'Load Test Tenant {i:03d}',
+                schema_name=f'load_test_{i:03d}',
+                domain=f'loadtest{i:03d}.com',
+                business_type=random.choice(['retail', 'healthcare', 'education', 'logistics', 'beauty']),
+                registration_number=f'202401{i:06d}',
+                tax_id=f'MY123456{i:04d}',
+                contact_email=f'contact{i:03d}@loadtest.com',
+                contact_phone=f'+6012345{i:04d}',
+                address=f'{i+1} Load Test Street',
+                city='Kuala Lumpur',
+                state='KUL',
+                postal_code='50000'
+            )
+            self.tenants.append(tenant)
+
+        # Create users for each tenant
+        self.users = []
+        for tenant in self.tenants:
+            for i in range(5):  # 5 users per tenant
+                user = User.objects.create_user(
+                    username=f'user_{tenant.schema_name}_{i}',
+                    email=f'user{i}@{tenant.domain}',
+                    password='test123',
+                    tenant=tenant,
+                    role=random.choice(['admin', 'staff', 'user']),
+                    first_name=f'User{i}',
+                    last_name=f'From {tenant.name}'
+                )
+                self.users.append(user)
+
+        # Create subscriptions for tenants
+        self.subscriptions = []
+        for tenant in self.tenants:
+            subscription = Subscription.objects.create(
+                tenant=tenant,
+                plan=random.choice(['basic', 'premium', 'enterprise']),
+                status='active',
+                start_date=datetime.now().date(),
+                end_date=datetime.now().date() + timedelta(days=30),
+                amount=Decimal(random.choice([99.00, 299.00, 999.00])),
+                currency='MYR',
+                billing_cycle='monthly',
+                auto_renew=True
+            )
+            self.subscriptions.append(subscription)
+
+        # Create test data for different modules
+        self.create_test_data()
+
+    def create_test_data(self):
+        """Create test data for different modules"""
+        # Products for retail tenants
+        self.products = []
+        retail_tenants = [t for t in self.tenants if t.business_type == 'retail']
+        for tenant in retail_tenants:
+            for i in range(50):
+                product = Product.objects.create(
+                    tenant=tenant,
+                    sku=f'{tenant.schema_name}_PRD_{i:04d}',
+                    name=f'Product {i} for {tenant.name}',
+                    description=f'Description for product {i}',
+                    category=random.choice(['electronics', 'clothing', 'food', 'books']),
+                    brand='Test Brand',
+                    barcode=f'123456789{i:04d}',
+                    unit='piece',
+                    current_stock=random.randint(10, 1000),
+                    minimum_stock=10,
+                    maximum_stock=1000,
+                    purchase_price=Decimal(random.uniform(10, 100)),
+                    selling_price=Decimal(random.uniform(20, 200)),
+                    tax_rate=6.0,
+                    is_active=True
+                )
+                self.products.append(product)
+
+        # Patients for healthcare tenants
+        self.patients = []
+        healthcare_tenants = [t for t in self.tenants if t.business_type == 'healthcare']
+        for tenant in healthcare_tenants:
+            for i in range(30):
+                patient = Patient.objects.create(
+                    tenant=tenant,
+                    patient_id=f'{tenant.schema_name}_PAT_{i:04d}',
+                    first_name=f'Patient{i}',
+                    last_name=f'Test{i}',
+                    ic_number=f'{random.randint(500101, 991231):02d}-{random.randint(10, 99):02d}-{random.randint(1000, 9999):04d}',
+                    gender=random.choice(['male', 'female']),
+                    date_of_birth=datetime.now() - timedelta(days=random.randint(365*18, 365*70)),
+                    blood_type=random.choice(['A+', 'A-', 'B+', 'B-', 'O+', 'O-', 'AB+', 'AB-']),
+                    email=f'patient{i}@{tenant.domain}',
+                    phone=f'+6012345{i:04d}',
+                    address=f'{i+1} Patient Street',
+                    city='Kuala Lumpur',
+                    state='KUL',
+                    postal_code='50000',
+                    is_active=True
+                )
+                self.patients.append(patient)
+
+        # Students for education tenants
+        self.students = []
+        education_tenants = [t for t in self.tenants if t.business_type == 'education']
+        for tenant in education_tenants:
+            for i in range(100):
+                student = Student.objects.create(
+                    tenant=tenant,
+                    student_id=f'{tenant.schema_name}_STU_{i:04d}',
+                    first_name=f'Student{i}',
+                    last_name=f'Test{i}',
+                    ic_number=f'{random.randint(500101, 991231):02d}-{random.randint(10, 99):02d}-{random.randint(1000, 9999):04d}',
+                    gender=random.choice(['male', 'female']),
+                    date_of_birth=datetime.now() - timedelta(days=random.randint(365*6, 365*18)),
+                    email=f'student{i}@{tenant.domain}',
+                    phone=f'+6012345{i:04d}',
+                    current_grade=random.choice(['Form 1', 'Form 2', 'Form 3', 'Form 4', 'Form 5']),
+                    stream=random.choice(['science', 'arts', 'commerce']),
+                    admission_date=datetime.now() - timedelta(days=random.randint(30, 365)),
+                    status='active',
+                    is_active=True
+                )
+                self.students.append(student)
+
+        # Shipments for logistics tenants
+        self.shipments = []
+        logistics_tenants = [t for t in self.tenants if t.business_type == 'logistics']
+        for tenant in logistics_tenants:
+            for i in range(25):
+                shipment = Shipment.objects.create(
+                    tenant=tenant,
+                    tracking_number=f'{tenant.schema_name}_TRK_{i:04d}',
+                    order_number=f'ORD_{i:06d}',
+                    sender_name=f'Sender {i}',
+                    receiver_name=f'Receiver {i}',
+                    sender_phone=f'+6012345{i:04d}',
+                    receiver_phone=f'+6012345{i:04d}',
+                    origin_state=random.choice(['KUL', 'PNG', 'JHR', 'KDH']),
+                    destination_state=random.choice(['KUL', 'PNG', 'JHR', 'KDH']),
+                    service_type=random.choice(['express', 'standard', 'economy']),
+                    package_type=random.choice(['document', 'parcel', 'freight']),
+                    weight=Decimal(random.uniform(0.5, 50)),
+                    length=Decimal(random.uniform(10, 100)),
+                    width=Decimal(random.uniform(10, 100)),
+                    height=Decimal(random.uniform(10, 100)),
+                    shipping_cost=Decimal(random.uniform(5, 200)),
+                    status=random.choice(['processing', 'in_transit', 'delivered']),
+                    priority=random.choice(['normal', 'urgent'])
+                )
+                self.shipments.append(shipment)
+
+        # Clients for beauty tenants
+        self.clients = []
+        beauty_tenants = [t for t in self.tenants if t.business_type == 'beauty']
+        for tenant in beauty_tenants:
+            for i in range(40):
+                client = Client.objects.create(
+                    tenant=tenant,
+                    client_number=f'{tenant.schema_name}_CLI_{i:04d}',
+                    first_name=f'Client{i}',
+                    last_name=f'Test{i}',
+                    ic_number=f'{random.randint(500101, 991231):02d}-{random.randint(10, 99):02d}-{random.randint(1000, 9999):04d}',
+                    gender=random.choice(['male', 'female']),
+                    date_of_birth=datetime.now() - timedelta(days=random.randint(365*18, 365*70)),
+                    email=f'client{i}@{tenant.domain}',
+                    phone=f'+6012345{i:04d}',
+                    membership_tier=random.choice(['basic', 'silver', 'gold', 'platinum']),
+                    loyalty_points=random.randint(0, 1000),
+                    total_spent=Decimal(random.uniform(0, 10000)),
+                    visit_count=random.randint(0, 50),
+                    is_active=True
+                )
+                self.clients.append(client)
+
+    def test_concurrent_tenant_operations(self):
+        """Test concurrent operations across multiple tenants"""
+        results = queue.Queue()
+        errors = queue.Queue()
+
+        def tenant_worker(tenant_id, worker_id):
+            """Worker function for tenant operations"""
+            start_time = time.time()
+            operations_completed = 0
+
+            try:
+                tenant = self.tenants[tenant_id]
+
+                # Perform various operations
+                for i in range(20):  # 20 operations per worker
+                    operation_type = random.choice(['read', 'write', 'update'])
+
+                    if operation_type == 'read':
+                        # Read operations
+                        users = User.objects.filter(tenant=tenant)
+                        subscription = Subscription.objects.filter(tenant=tenant).first()
+                        operations_completed += 2
+
+                    elif operation_type == 'write':
+                        # Write operations (create new records)
+                        if tenant.business_type == 'retail':
+                            Product.objects.create(
+                                tenant=tenant,
+                                sku=f'LOAD_{worker_id}_{i:04d}',
+                                name=f'Load Test Product {worker_id}-{i}',
+                                category='electronics',
+                                unit='piece',
+                                current_stock=100,
+                                minimum_stock=10,
+                                purchase_price=Decimal('50.00'),
+                                selling_price=Decimal('100.00'),
+                                tax_rate=6.0,
+                                is_active=True
+                            )
+                        elif tenant.business_type == 'healthcare':
+                            Patient.objects.create(
+                                tenant=tenant,
+                                patient_id=f'LOAD_{worker_id}_{i:04d}',
+                                first_name=f'Load Patient {worker_id}-{i}',
+                                ic_number=f'{random.randint(500101, 991231):02d}-{random.randint(10, 99):02d}-{random.randint(1000, 9999):04d}',
+                                gender='male',
+                                date_of_birth=datetime.now() - timedelta(days=365*30),
+                                email=f'load{worker_id}-{i}@{tenant.domain}',
+                                phone=f'+6012345{worker_id:02d}{i:02d}',
+                                is_active=True
+                            )
+                        operations_completed += 1
+
+                    elif operation_type == 'update':
+                        # Update operations
+                        tenant.name = f'Updated Tenant {tenant_id} at {time.time()}'
+                        tenant.save()
+
+                        # Update user data
+                        users = User.objects.filter(tenant=tenant)
+                        for user in users[:5]:  # Update first 5 users
+                            user.last_login = datetime.now()
+                            user.save()
+                        operations_completed += len(users[:5]) + 1
+
+                    # Small delay to simulate real usage
+                    time.sleep(0.01)
+
+                end_time = time.time()
+                results.put({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'operations_completed': operations_completed,
+                    'time_taken': end_time - start_time,
+                    'success': True
+                })
+
+            except Exception as e:
+                errors.put({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'error': str(e),
+                    'time_taken': time.time() - start_time,
+                    'success': False
+                })
+
+        # Start concurrent workers
+        start_time = time.time()
+        threads = []
+
+        # Create workers for different tenants (concurrency level)
+        concurrency_level = 15
+        for i in range(concurrency_level):
+            tenant_id = i % len(self.tenants)
+            thread = threading.Thread(
+                target=tenant_worker,
+                args=(tenant_id, i)
+            )
+            threads.append(thread)
+
+        # Start all threads
+        for thread in threads:
+            thread.start()
+
+        # Wait for all threads to complete
+        for thread in threads:
+            thread.join()
+
+        total_time = time.time() - start_time
+
+        # Collect results
+        successful_operations = []
+        while not results.empty():
+            successful_operations.append(results.get())
+
+        failed_operations = []
+        while not errors.empty():
+            failed_operations.append(errors.get())
+
+        # Analyze results
+        total_operations = sum(op['operations_completed'] for op in successful_operations)
+        operations_per_second = total_operations / total_time
+        success_rate = len(successful_operations) / (len(successful_operations) + len(failed_operations)) * 100
+
+        # Performance assertions
+        self.assertGreaterEqual(success_rate, 95.0,
+                              "Success rate should be at least 95% for concurrent operations")
+        self.assertGreater(operations_per_second, 10,
+                           "Should handle at least 10 operations per second")
+
+        # Log performance metrics
+        print(f"\nConcurrent Tenant Operations Results:")
+        print(f"Total time: {total_time:.2f}s")
+        print(f"Total operations: {total_operations}")
+        print(f"Operations per second: {operations_per_second:.1f}")
+        print(f"Success rate: {success_rate:.1f}%")
+        print(f"Successful workers: {len(successful_operations)}")
+        print(f"Failed workers: {len(failed_operations)}")
+
+        if failed_operations:
+            print(f"\nFailed operations:")
+            for failure in failed_operations:
+                print(f"  Worker {failure['worker_id']}: {failure['error']}")
+
+    def test_database_connection_pooling_under_load(self):
+        """Test database connection pooling under heavy load"""
+        connection_metrics = []
+
+        def connection_test_worker(worker_id, operations):
+            """Worker to test database connections"""
+            worker_metrics = {
+                'worker_id': worker_id,
+                'connections': [],
+                'success_count': 0,
+                'error_count': 0
+            }
+
+            for i in range(operations):
+                start_time = time.time()
+                try:
+                    with connection.cursor() as cursor:
+                        # Execute query with tenant isolation
+                        tenant = self.tenants[worker_id % len(self.tenants)]
+                        cursor.execute(f'SET search_path TO "{tenant.schema_name}", public;')
+                        cursor.execute("SELECT COUNT(*) FROM auth_user;")
+                        count = cursor.fetchone()[0]
+
+                    connection_time = time.time() - start_time
+                    worker_metrics['connections'].append(connection_time)
+                    worker_metrics['success_count'] += 1
+
+                    # Small delay to simulate real usage
+                    time.sleep(0.001)
+
+                except Exception as e:
+                    worker_metrics['error_count'] += 1
+                    connection_time = time.time() - start_time
+                    worker_metrics['connections'].append(connection_time)
+
+            return worker_metrics
+
+        # Test with different load levels
+        load_levels = [10, 25, 50, 100]
+
+        for load_level in load_levels:
+            print(f"\nTesting connection pooling with {load_level} concurrent connections:")
+
+            threads = []
+            results = queue.Queue()
+
+            # Create worker threads
+            for i in range(load_level):
+                thread = threading.Thread(
+                    target=lambda q, wid: q.put(connection_test_worker(wid, 20)),
+                    args=(results, i)
+                )
+                threads.append(thread)
+
+            # Start all threads
+            start_time = time.time()
+            for thread in threads:
+                thread.start()
+
+            # Wait for completion
+            for thread in threads:
+                thread.join()
+
+            total_time = time.time() - start_time
+
+            # Collect and analyze results
+            all_metrics = []
+            while not results.empty():
+                all_metrics.append(results.get())
+
+            total_connections = sum(m['success_count'] + m['error_count'] for m in all_metrics)
+            successful_connections = sum(m['success_count'] for m in all_metrics)
+            connection_times = [time for m in all_metrics for time in m['connections']]
+
+            if connection_times:
+                avg_connection_time = statistics.mean(connection_times)
+                max_connection_time = max(connection_times)
+                min_connection_time = min(connection_times)
+                connections_per_second = total_connections / total_time
+                success_rate = successful_connections / total_connections * 100
+
+                # Performance assertions
+                self.assertLess(avg_connection_time, 0.05,
+                               f"Average connection time should be under 50ms at {load_level} connections")
+                self.assertLess(max_connection_time, 0.2,
+                               f"Maximum connection time should be under 200ms at {load_level} connections")
+                self.assertGreaterEqual(success_rate, 98.0,
+                                      f"Success rate should be at least 98% at {load_level} connections")
+
+                print(f"  Average connection time: {avg_connection_time:.3f}s")
+                print(f"  Max connection time: {max_connection_time:.3f}s")
+                print(f"  Connections per second: {connections_per_second:.1f}")
+                print(f"  Success rate: {success_rate:.1f}%")
+
+    def test_schema_isolation_performance(self):
+        """Test performance of schema isolation under load"""
+        isolation_metrics = []
+
+        def schema_isolation_worker(tenant_id, worker_id):
+            """Worker to test schema isolation"""
+            start_time = time.time()
+            operations_completed = 0
+
+            try:
+                tenant = self.tenants[tenant_id]
+
+                # Test schema-specific operations
+                with connection.cursor() as cursor:
+                    # Switch to tenant schema
+                    cursor.execute(f'SET search_path TO "{tenant.schema_name}", public;')
+
+                    # Perform operations in tenant schema
+                    for i in range(10):
+                        # Count users in tenant schema
+                        cursor.execute("SELECT COUNT(*) FROM auth_user;")
+                        user_count = cursor.fetchone()[0]
+
+                        # Get tenant-specific data
+                        if tenant.business_type == 'retail':
+                            cursor.execute("SELECT COUNT(*) FROM core_product;")
+                            product_count = cursor.fetchone()[0]
+                        elif tenant.business_type == 'healthcare':
+                            cursor.execute("SELECT COUNT(*) FROM healthcare_patient;")
+                            patient_count = cursor.fetchone()[0]
+
+                        operations_completed += 1
+
+                        # Small delay
+                        time.sleep(0.001)
+
+                end_time = time.time()
+
+                isolation_metrics.append({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'operations_completed': operations_completed,
+                    'time_taken': end_time - start_time,
+                    'success': True
+                })
+
+            except Exception as e:
+                isolation_metrics.append({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'error': str(e),
+                    'time_taken': time.time() - start_time,
+                    'success': False
+                })
+
+        # Test schema isolation with concurrent access
+        threads = []
+        for i in range(30):  # 30 concurrent workers
+            tenant_id = i % len(self.tenants)
+            thread = threading.Thread(
+                target=schema_isolation_worker,
+                args=(tenant_id, i)
+            )
+            threads.append(thread)
+
+        start_time = time.time()
+        for thread in threads:
+            thread.start()
+
+        for thread in threads:
+            thread.join()
+
+        total_time = time.time() - start_time
+
+        # Analyze isolation performance
+        successful_ops = [m for m in isolation_metrics if m['success']]
+        failed_ops = [m for m in isolation_metrics if not m['success']]
+
+        total_operations = sum(op['operations_completed'] for op in successful_ops)
+        success_rate = len(successful_ops) / len(isolation_metrics) * 100
+        operations_per_second = total_operations / total_time
+
+        if successful_ops:
+            avg_time_per_op = statistics.mean([op['time_taken'] / op['operations_completed'] for op in successful_ops])
+
+            # Performance assertions
+            self.assertLess(avg_time_per_op, 0.01,
+                           "Average time per schema operation should be under 10ms")
+            self.assertGreaterEqual(success_rate, 95.0,
+                                  "Schema isolation success rate should be at least 95%")
+            self.assertGreater(operations_per_second, 50,
+                               "Should handle at least 50 schema operations per second")
+
+        print(f"\nSchema Isolation Performance:")
+        print(f"Total time: {total_time:.2f}s")
+        print(f"Total operations: {total_operations}")
+        print(f"Operations per second: {operations_per_second:.1f}")
+        print(f"Success rate: {success_rate:.1f}%")
+        if successful_ops:
+            print(f"Average time per operation: {avg_time_per_op:.4f}s")
+
+    def test_resource_usage_optimization(self):
+        """Test resource usage optimization under multi-tenant load"""
+        import psutil
+        import os
+
+        process = psutil.Process(os.getpid())
+
+        # Monitor resource usage during load test
+        def resource_monitor_worker(duration, results_queue):
+            """Worker to monitor resource usage"""
+            start_time = time.time()
+            memory_samples = []
+            cpu_samples = []
+
+            while time.time() - start_time < duration:
+                memory_info = process.memory_info()
+                cpu_percent = process.cpu_percent()
+
+                memory_samples.append(memory_info.rss / 1024 / 1024)  # MB
+                cpu_samples.append(cpu_percent)
+
+                time.sleep(0.1)  # Sample every 100ms
+
+            results_queue.put({
+                'memory_samples': memory_samples,
+                'cpu_samples': cpu_samples,
+                'duration': duration
+            })
+
+        def load_worker(worker_id, operations):
+            """Load generation worker"""
+            for i in range(operations):
+                try:
+                    # Random tenant operations
+                    tenant = random.choice(self.tenants)
+
+                    # Perform random database operations
+                    with connection.cursor() as cursor:
+                        cursor.execute(f'SET search_path TO "{tenant.schema_name}", public;')
+                        cursor.execute("SELECT COUNT(*) FROM auth_user;")
+
+                    # Small delay
+                    time.sleep(0.005)
+
+                except Exception as e:
+                    print(f"Worker {worker_id} error: {e}")
+
+        # Start resource monitoring
+        monitor_results = queue.Queue()
+        monitor_thread = threading.Thread(
+            target=resource_monitor_worker,
+            args=(10, monitor_results)  # Monitor for 10 seconds
+        )
+        monitor_thread.start()
+
+        # Start load generation
+        start_time = time.time()
+        threads = []
+
+        # Create load workers
+        for i in range(50):  # 50 concurrent workers
+            thread = threading.Thread(
+                target=load_worker,
+                args=(i, 100)  # Each worker performs 100 operations
+            )
+            threads.append(thread)
+
+        for thread in threads:
+            thread.start()
+
+        for thread in threads:
+            thread.join()
+
+        total_time = time.time() - start_time
+
+        # Wait for monitoring to complete
+        monitor_thread.join()
+        resource_data = monitor_results.get()
+
+        # Analyze resource usage
+        memory_samples = resource_data['memory_samples']
+        cpu_samples = resource_data['cpu_samples']
+
+        avg_memory = statistics.mean(memory_samples)
+        max_memory = max(memory_samples)
+        avg_cpu = statistics.mean(cpu_samples)
+        max_cpu = max(cpu_samples)
+
+        total_operations = 50 * 100  # 50 workers * 100 operations each
+        operations_per_second = total_operations / total_time
+
+        # Performance assertions
+        self.assertLess(avg_memory, 1000,  # 1GB
+                       "Average memory usage should be under 1GB")
+        self.assertLess(max_memory, 1500,  # 1.5GB
+                       "Peak memory usage should be under 1.5GB")
+        self.assertLess(avg_cpu, 80,  # 80%
+                       "Average CPU usage should be under 80%")
+        self.assertGreater(operations_per_second, 25,
+                          "Should handle at least 25 operations per second under load")
+
+        print(f"\nResource Usage Optimization Results:")
+        print(f"Total operations: {total_operations}")
+        print(f"Operations per second: {operations_per_second:.1f}")
+        print(f"Average memory usage: {avg_memory:.1f} MB")
+        print(f"Peak memory usage: {max_memory:.1f} MB")
+        print(f"Average CPU usage: {avg_cpu:.1f}%")
+        print(f"Peak CPU usage: {max_cpu:.1f}%")
+
+    def test_scalability_benchmark(self):
+        """Test scalability with increasing load"""
+        scalability_results = []
+
+        # Test with different tenant counts
+        tenant_counts = [5, 10, 15, 20]
+
+        for tenant_count in tenant_counts:
+            print(f"\nTesting scalability with {tenant_count} tenants:")
+
+            # Use subset of tenants
+            test_tenants = self.tenants[:tenant_count]
+
+            def scalability_worker(operations):
+                """Worker for scalability testing"""
+                for i in range(operations):
+                    try:
+                        tenant = random.choice(test_tenants)
+
+                        # Perform tenant-specific operations
+                        with connection.cursor() as cursor:
+                            cursor.execute(f'SET search_path TO "{tenant.schema_name}", public;')
+                            cursor.execute("SELECT COUNT(*) FROM auth_user;")
+
+                        # Simulate processing time
+                        time.sleep(0.01)
+
+                    except Exception as e:
+                        continue
+
+            # Run test with increasing concurrency
+            concurrency_levels = [5, 10, 20]
+
+            for concurrency in concurrency_levels:
+                start_time = time.time()
+                threads = []
+
+                # Create worker threads
+                for i in range(concurrency):
+                    thread = threading.Thread(
+                        target=scalability_worker,
+                        args=(20,)  # 20 operations per worker
+                    )
+                    threads.append(thread)
+
+                # Start and wait for completion
+                for thread in threads:
+                    thread.start()
+
+                for thread in threads:
+                    thread.join()
+
+                total_time = time.time() - start_time
+                total_operations = concurrency * 20
+                operations_per_second = total_operations / total_time
+
+                scalability_results.append({
+                    'tenant_count': tenant_count,
+                    'concurrency': concurrency,
+                    'total_time': total_time,
+                    'operations_per_second': operations_per_second
+                })
+
+                print(f"  Concurrency {concurrency}: {operations_per_second:.1f} ops/sec")
+
+        # Analyze scalability
+        print(f"\nScalability Analysis:")
+        for result in scalability_results:
+            throughput = result['operations_per_second']
+            tenant_count = result['tenant_count']
+            concurrency = result['concurrency']
+
+            # Calculate throughput per tenant
+            throughput_per_tenant = throughput / tenant_count
+
+            print(f"  {tenant_count} tenants, {concurrency} concurrent: "
+                  f"{throughput:.1f} ops/sec ({throughput_per_tenant:.1f} per tenant)")
+
+        # Performance assertions for scalability
+        # Throughput should not decrease significantly with more tenants
+        baseline_throughput = scalability_results[0]['operations_per_second']
+        max_throughput = max(r['operations_per_second'] for r in scalability_results)
+
+        self.assertGreater(max_throughput, baseline_throughput * 0.5,
+                          "Throughput should not degrade by more than 50% under load")
+
+    def test_multi_tenant_transaction_performance(self):
+        """Test transaction performance across multiple tenants"""
+        transaction_metrics = []
+
+        def transaction_worker(tenant_id, worker_id):
+            """Worker for transaction testing"""
+            start_time = time.time()
+
+            try:
+                tenant = self.tenants[tenant_id]
+
+                # Perform transactions in tenant schema
+                with transaction.atomic():
+                    with connection.cursor() as cursor:
+                        cursor.execute(f'SET search_path TO "{tenant.schema_name}", public;')
+
+                        # Create multiple records in a transaction
+                        for i in range(5):
+                            cursor.execute(
+                                "INSERT INTO auth_user (username, email, password, tenant_id, is_active) "
+                                "VALUES (%s, %s, %s, %s, %s) RETURNING id;",
+                                [f'tx_user_{worker_id}_{i}', f'user{i}@{tenant.domain}', 'hash', tenant.id, True]
+                            )
+
+                            # Update tenant stats
+                            cursor.execute(
+                                "UPDATE core_tenant SET name = %s WHERE id = %s;",
+                                [f'Updated at {time.time()}', tenant.id]
+                            )
+
+                end_time = time.time()
+
+                transaction_metrics.append({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'time_taken': end_time - start_time,
+                    'success': True
+                })
+
+            except Exception as e:
+                transaction_metrics.append({
+                    'worker_id': worker_id,
+                    'tenant_id': tenant_id,
+                    'error': str(e),
+                    'time_taken': time.time() - start_time,
+                    'success': False
+                })
+
+        # Test concurrent transactions
+        threads = []
+        for i in range(40):  # 40 concurrent transaction workers
+            tenant_id = i % len(self.tenants)
+            thread = threading.Thread(
+                target=transaction_worker,
+                args=(tenant_id, i)
+            )
+            threads.append(thread)
+
+        start_time = time.time()
+        for thread in threads:
+            thread.start()
+
+        for thread in threads:
+            thread.join()
+
+        total_time = time.time() - start_time
+
+        # Analyze transaction performance
+        successful_tx = [m for m in transaction_metrics if m['success']]
+        failed_tx = [m for m in transaction_metrics if not m['success']]
+
+        success_rate = len(successful_tx) / len(transaction_metrics) * 100
+
+        if successful_tx:
+            avg_tx_time = statistics.mean([tx['time_taken'] for tx in successful_tx])
+            transactions_per_second = len(successful_tx) / total_time
+
+            # Performance assertions
+            self.assertLess(avg_tx_time, 0.1,
+                           "Average transaction time should be under 100ms")
+            self.assertGreaterEqual(success_rate, 95.0,
+                                  "Transaction success rate should be at least 95%")
+            self.assertGreater(transactions_per_second, 20,
+                               "Should handle at least 20 transactions per second")
+
+        print(f"\nMulti-Tenant Transaction Performance:")
+        print(f"Total time: {total_time:.2f}s")
+        print(f"Total transactions: {len(successful_tx)}")
+        print(f"Transactions per second: {len(successful_tx) / total_time:.1f}")
+        print(f"Success rate: {success_rate:.1f}%")
+        if successful_tx:
+            print(f"Average transaction time: {avg_tx_time:.3f}s")

backend/tests/performance/test_api_performance.py

@@ -0,0 +1,441 @@
+"""
+Performance Tests for API Endpoints
+
+Tests for API performance optimization:
+- Response time optimization
+- Concurrency handling
+- Rate limiting efficiency
+- Caching strategies
+- Payload size optimization
+
+Author: Claude
+"""
+
+import pytest
+import time
+import statistics
+import threading
+import requests
+from django.test import TestCase, Client
+from django.urls import reverse
+from django.contrib.auth import get_user_model
+from django.core.cache import cache
+from django.conf import settings
+from decimal import Decimal
+from datetime import date
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.retail.models.product import Product
+
+User = get_user_model()
+
+
+class APIPerformanceTest(TestCase):
+    """Test cases for API performance optimization"""
+
+    def setUp(self):
+        self.client = Client()
+
+        # Create test tenant and user
+        self.tenant = Tenant.objects.create(
+            name='API Performance Test',
+            schema_name='api_perf_test',
+            domain='apiperf.com',
+            business_type='retail'
+        )
+
+        self.user = User.objects.create_user(
+            username='testuser',
+            email='test@example.com',
+            password='test123',
+            tenant=self.tenant,
+            role='admin'
+        )
+
+        # Create test data
+        self.products = []
+        for i in range(100):
+            product = Product.objects.create(
+                tenant=self.tenant,
+                sku=f'API-TEST-{i:06d}',
+                name=f'API Test Product {i}',
+                description=f'Description for API test product {i}',
+                category='electronics',
+                brand='Test Brand',
+                barcode=f'123456789{i:04d}',
+                unit='piece',
+                current_stock=100 + i,
+                minimum_stock=10,
+                maximum_stock=500,
+                purchase_price=Decimal('50.00') + (i * 0.1),
+                selling_price=Decimal('100.00') + (i * 0.2),
+                tax_rate=10.0,
+                is_active=True
+            )
+            self.products.append(product)
+
+    def test_api_response_time_optimization(self):
+        """Test API response time optimization"""
+        # Test various API endpoints
+        endpoints = [
+            ('api:tenant-list', 'GET', {}),
+            ('api:user-list', 'GET', {}),
+            ('api:product-list', 'GET', {}),
+            ('api:tenant-detail', 'GET', {'pk': self.tenant.id}),
+            ('api:user-detail', 'GET', {'pk': self.user.id}),
+            ('api:product-detail', 'GET', {'pk': self.products[0].id}),
+        ]
+
+        response_times = {}
+
+        for endpoint_name, method, params in endpoints:
+            times = []
+
+            # Warm up cache
+            for _ in range(3):
+                if method == 'GET':
+                    self.client.get(reverse(endpoint_name, kwargs=params))
+                elif method == 'POST':
+                    self.client.post(reverse(endpoint_name, kwargs=params))
+
+            # Measure response times
+            for _ in range(10):
+                start_time = time.time()
+
+                if method == 'GET':
+                    response = self.client.get(reverse(endpoint_name, kwargs=params))
+                elif method == 'POST':
+                    response = self.client.post(reverse(endpoint_name, kwargs=params))
+
+                response_time = time.time() - start_time
+                times.append(response_time)
+
+                # Verify response is successful
+                self.assertEqual(response.status_code, 200)
+
+            avg_time = statistics.mean(times)
+            max_time = max(times)
+            min_time = min(times)
+
+            response_times[endpoint_name] = {
+                'avg': avg_time,
+                'max': max_time,
+                'min': min_time,
+                'times': times
+            }
+
+            # Performance assertions
+            self.assertLess(avg_time, 0.5, f"Average response time for {endpoint_name} should be under 500ms")
+            self.assertLess(max_time, 1.0, f"Maximum response time for {endpoint_name} should be under 1s")
+
+        # Log performance metrics
+        print(f"\nAPI Response Time Performance:")
+        for endpoint, metrics in response_times.items():
+            print(f"{endpoint}: avg={metrics['avg']:.3f}s, max={metrics['max']:.3f}s, min={metrics['min']:.3f}s")
+
+    def test_concurrent_request_handling(self):
+        """Test concurrent request handling"""
+        def make_request(request_id, results):
+            start_time = time.time()
+            try:
+                response = self.client.get(reverse('api:product-list'))
+                response_time = time.time() - start_time
+                results.append({
+                    'request_id': request_id,
+                    'success': response.status_code == 200,
+                    'response_time': response_time,
+                    'status_code': response.status_code
+                })
+            except Exception as e:
+                results.append({
+                    'request_id': request_id,
+                    'success': False,
+                    'error': str(e),
+                    'response_time': time.time() - start_time
+                })
+
+        # Test with different concurrency levels
+        concurrency_levels = [10, 25, 50]
+
+        for concurrency in concurrency_levels:
+            results = []
+            threads = []
+
+            # Create concurrent requests
+            for i in range(concurrency):
+                thread = threading.Thread(
+                    target=make_request,
+                    args=(i, results)
+                )
+                threads.append(thread)
+
+            # Start all threads
+            start_time = time.time()
+            for thread in threads:
+                thread.start()
+
+            # Wait for all threads to complete
+            for thread in threads:
+                thread.join()
+
+            total_time = time.time() - start_time
+
+            # Analyze results
+            successful_requests = [r for r in results if r['success']]
+            failed_requests = [r for r in results if not r['success']]
+
+            success_rate = len(successful_requests) / len(results) * 100
+            avg_response_time = statistics.mean([r['response_time'] for r in results])
+
+            # Performance assertions
+            self.assertGreaterEqual(success_rate, 95.0,
+                                  f"Success rate should be at least 95% for {concurrency} concurrent requests")
+            self.assertLess(total_time, 5.0,
+                           f"Total time for {concurrency} concurrent requests should be under 5s")
+
+            print(f"\nConcurrency Test ({concurrency} requests):")
+            print(f"Success rate: {success_rate:.1f}%")
+            print(f"Total time: {total_time:.3f}s")
+            print(f"Average response time: {avg_response_time:.3f}s")
+            print(f"Failed requests: {len(failed_requests)}")
+
+    def test_rate_limiting_efficiency(self):
+        """Test rate limiting efficiency"""
+        # This test assumes rate limiting is implemented
+        # Make rapid requests to test rate limiting
+        request_results = []
+
+        for i in range(100):
+            start_time = time.time()
+            response = self.client.get(reverse('api:product-list'))
+            response_time = time.time() - start_time
+
+            request_results.append({
+                'request_number': i,
+                'status_code': response.status_code,
+                'response_time': response_time,
+                'timestamp': time.time()
+            })
+
+        # Analyze rate limiting effectiveness
+        successful_requests = [r for r in request_results if r['status_code'] == 200]
+        rate_limited_requests = [r for r in request_results if r['status_code'] == 429]
+
+        print(f"\nRate Limiting Test:")
+        print(f"Total requests: {len(request_results)}")
+        print(f"Successful requests: {len(successful_requests)}")
+        print(f"Rate limited requests: {len(rate_limited_requests)}")
+
+        # If rate limiting is implemented, some requests should be limited
+        if len(rate_limited_requests) > 0:
+            print(f"Rate limiting is working - {len(rate_limited_requests)} requests were limited")
+
+        # Response times should remain consistent even under load
+        response_times = [r['response_time'] for r in successful_requests]
+        if response_times:
+            avg_response_time = statistics.mean(response_times)
+            max_response_time = max(response_times)
+
+            self.assertLess(avg_response_time, 0.5,
+                           "Average response time should remain under 500ms even with rate limiting")
+            print(f"Average response time for successful requests: {avg_response_time:.3f}s")
+
+    def test_caching_strategies(self):
+        """Test caching strategies performance"""
+        # Clear cache before testing
+        cache.clear()
+
+        # Test cache hit/miss performance
+        endpoint = reverse('api:product-list')
+
+        # First request (cache miss)
+        start_time = time.time()
+        response1 = self.client.get(endpoint)
+        cache_miss_time = time.time() - start_time
+
+        # Second request (cache hit)
+        start_time = time.time()
+        response2 = self.client.get(endpoint)
+        cache_hit_time = time.time() - start_time
+
+        # Multiple cache hits
+        cache_hit_times = []
+        for _ in range(10):
+            start_time = time.time()
+            response = self.client.get(endpoint)
+            cache_hit_times.append(time.time() - start_time)
+
+        avg_cache_hit_time = statistics.mean(cache_hit_times)
+
+        # Performance assertions
+        self.assertLess(cache_miss_time, 1.0, "Cache miss should complete within 1s")
+        self.assertLess(cache_hit_time, 0.1, "Cache hit should complete within 100ms")
+        self.assertLess(avg_cache_hit_time, 0.05, "Average cache hit should be under 50ms")
+
+        # Cache hit should be faster than cache miss
+        self.assertLess(avg_cache_hit_time, cache_miss_time * 0.5,
+                       "Cache hit should be significantly faster than cache miss")
+
+        print(f"\nCaching Strategy Performance:")
+        print(f"Cache miss time: {cache_miss_time:.3f}s")
+        print(f"First cache hit time: {cache_hit_time:.3f}s")
+        print(f"Average cache hit time: {avg_cache_hit_time:.3f}s")
+        print(f"Cache improvement: {(cache_miss_time / avg_cache_hit_time):.1f}x")
+
+    def test_payload_size_optimization(self):
+        """Test payload size optimization"""
+        # Test different payload sizes
+        test_sizes = [10, 50, 100, 500]
+
+        for size in test_sizes:
+            # Create test data
+            test_products = []
+            for i in range(size):
+                test_products.append({
+                    'sku': f'PAYLOAD-{i:06d}',
+                    'name': f'Payload Test Product {i}',
+                    'description': 'A' * 100,  # Long description
+                    'category': 'electronics',
+                    'brand': 'Test Brand',
+                    'current_stock': 100,
+                    'purchase_price': '50.00',
+                    'selling_price': '100.00'
+                })
+
+            # Test different response formats
+            # Full payload
+            start_time = time.time()
+            response = self.client.get(reverse('api:product-list'))
+            full_payload_time = time.time() - start_time
+            full_payload_size = len(response.content)
+
+            # Paginated payload (assuming pagination is implemented)
+            start_time = time.time()
+            response = self.client.get(reverse('api:product-list') + '?page=1&page_size=20')
+            paginated_time = time.time() - start_time
+            paginated_size = len(response.content)
+
+            # Fields-limited payload
+            start_time = time.time()
+            response = self.client.get(reverse('api:product-list') + '?fields=id,name,sku')
+            fields_limited_time = time.time() - start_time
+            fields_limited_size = len(response.content)
+
+            # Performance assertions
+            self.assertLess(full_payload_time, 2.0,
+                           f"Full payload request for {size} items should complete within 2s")
+            self.assertLess(paginated_time, 0.5,
+                           f"Paginated request should be faster")
+            self.assertLess(fields_limited_time, 0.3,
+                           f"Fields-limited request should be fastest")
+
+            # Size assertions
+            self.assertLess(paginated_size, full_payload_size * 0.3,
+                           f"Paginated payload should be much smaller for {size} items")
+            self.assertLess(fields_limited_size, full_payload_size * 0.2,
+                           f"Fields-limited payload should be smallest")
+
+            print(f"\nPayload Optimization Test ({size} items):")
+            print(f"Full payload: {full_payload_time:.3f}s, {full_payload_size} bytes")
+            print(f"Paginated: {paginated_time:.3f}s, {paginated_size} bytes")
+            print(f"Fields limited: {fields_limited_time:.3f}s, {fields_limited_size} bytes")
+
+    def test_database_query_optimization(self):
+        """Test database query optimization in API calls"""
+        # Test N+1 query problems
+        # First, test without optimization
+        start_time = time.time()
+        response = self.client.get(reverse('api:product-list'))
+        unoptimized_time = time.time() - start_time
+
+        # Test with select_related (assuming optimization is implemented)
+        start_time = time.time()
+        response = self.client.get(reverse('api:product-list') + '?select_related=tenant')
+        optimized_time = time.time() - start_time
+
+        # Test with pagination
+        start_time = time.time()
+        response = self.client.get(reverse('api:product-list') + '?page=1&page_size=10')
+        paginated_time = time.time() - start_time
+
+        # Performance assertions
+        self.assertLess(unoptimized_time, 1.0, "Unoptimized query should complete within 1s")
+        self.assertLess(optimized_time, unoptimized_time * 0.8,
+                       "Optimized query should be faster")
+        self.assertLess(paginated_time, unoptimized_time * 0.3,
+                       "Paginated query should be much faster")
+
+        print(f"\nDatabase Query Optimization:")
+        print(f"Unoptimized query: {unoptimized_time:.3f}s")
+        print(f"Optimized query: {optimized_time:.3f}s")
+        print(f"Paginated query: {paginated_time:.3f}s")
+
+    def test_memory_usage_optimization(self):
+        """Test memory usage optimization"""
+        import psutil
+        import os
+
+        process = psutil.Process(os.getpid())
+
+        # Test memory usage with large datasets
+        initial_memory = process.memory_info().rss / 1024 / 1024  # MB
+
+        # Make multiple requests with large payloads
+        for i in range(10):
+            response = self.client.get(reverse('api:product-list'))
+            # Process response to simulate real usage
+            data = response.json()
+
+        peak_memory = process.memory_info().rss / 1024 / 1024  # MB
+        memory_increase = peak_memory - initial_memory
+
+        # Performance assertions
+        self.assertLess(memory_increase, 50,
+                       "Memory increase should be under 50MB for large dataset processing")
+
+        print(f"\nMemory Usage Optimization:")
+        print(f"Initial memory: {initial_memory:.1f} MB")
+        print(f"Peak memory: {peak_memory:.1f} MB")
+        print(f"Memory increase: {memory_increase:.1f} MB")
+
+    def test_authentication_performance(self):
+        """Test authentication performance"""
+        # Test login performance
+        login_data = {
+            'username': 'testuser',
+            'password': 'test123'
+        }
+
+        login_times = []
+        for _ in range(10):
+            start_time = time.time()
+            response = self.client.post(reverse('api:login'), login_data)
+            login_time = time.time() - start_time
+            login_times.append(login_time)
+
+            self.assertEqual(response.status_code, 200)
+
+        avg_login_time = statistics.mean(login_times)
+
+        # Test authenticated request performance
+        self.client.login(username='testuser', password='test123')
+
+        auth_request_times = []
+        for _ in range(10):
+            start_time = time.time()
+            response = self.client.get(reverse('api:product-list'))
+            auth_request_time = time.time() - start_time
+            auth_request_times.append(auth_request_time)
+
+            self.assertEqual(response.status_code, 200)
+
+        avg_auth_request_time = statistics.mean(auth_request_times)
+
+        # Performance assertions
+        self.assertLess(avg_login_time, 0.5, "Average login time should be under 500ms")
+        self.assertLess(avg_auth_request_time, 0.2, "Average authenticated request time should be under 200ms")
+
+        print(f"\nAuthentication Performance:")
+        print(f"Average login time: {avg_login_time:.3f}s")
+        print(f"Average authenticated request time: {avg_auth_request_time:.3f}s")

backend/tests/performance/test_database_performance.py

@@ -0,0 +1,418 @@
+"""
+Performance Tests for Database Operations
+
+Tests for database performance optimization:
+- Query optimization
+- Connection pooling efficiency
+- Multi-tenant query performance
+- Index usage validation
+- Bulk operations performance
+
+Author: Claude
+"""
+
+import pytest
+import time
+import statistics
+from django.test import TestCase
+from django.db import connection, connections, transaction
+from django.contrib.auth import get_user_model
+from django.core.management import call_command
+from django.conf import settings
+from django.db.utils import OperationalError
+from decimal import Decimal
+from datetime import date, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.retail.models.product import Product
+from backend.src.modules.healthcare.models.patient import Patient
+from backend.src.modules.education.models.student import Student
+
+User = get_user_model()
+
+
+class DatabasePerformanceTest(TestCase):
+    """Test cases for database performance optimization"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Performance Test Sdn Bhd',
+            schema_name='performance_test',
+            domain='performancetest.com',
+            business_type='retail'
+        )
+
+    def test_query_performance_with_indexes(self):
+        """Test query performance with proper indexing"""
+        # Create test data
+        products = []
+        for i in range(1000):
+            products.append(Product(
+                tenant=self.tenant,
+                sku=f'PRD-{i:06d}',
+                name=f'Product {i}',
+                description=f'Description for product {i}',
+                category='electronics',
+                brand='Test Brand',
+                barcode=f'123456789{i:04d}',
+                unit='piece',
+                current_stock=100 + i,
+                minimum_stock=10,
+                maximum_stock=500,
+                purchase_price=Decimal('50.00') + (i * 0.1),
+                selling_price=Decimal('100.00') + (i * 0.2),
+                tax_rate=10.0,
+                is_active=True
+            ))
+
+        # Bulk create for performance
+        start_time = time.time()
+        Product.objects.bulk_create(products)
+        bulk_create_time = time.time() - start_time
+
+        # Test indexed query performance
+        start_time = time.time()
+        products_by_sku = Product.objects.filter(sku__startswith='PRD-000')
+        indexed_query_time = time.time() - start_time
+
+        # Test non-indexed query performance (description)
+        start_time = time.time()
+        products_by_desc = Product.objects.filter(description__contains='Description for product')
+        non_indexed_query_time = time.time() - start_time
+
+        # Test tenant-isolated query performance
+        start_time = time.time()
+        tenant_products = Product.objects.filter(tenant=self.tenant)
+        tenant_query_time = time.time() - start_time
+
+        # Performance assertions
+        self.assertLess(bulk_create_time, 5.0, "Bulk create should complete within 5 seconds")
+        self.assertLess(indexed_query_time, 0.1, "Indexed query should complete within 100ms")
+        self.assertLess(tenant_query_time, 0.1, "Tenant query should complete within 100ms")
+
+        # Indexed query should be faster than non-indexed
+        self.assertLess(indexed_query_time, non_indexed_query_time * 2,
+                       "Indexed query should be significantly faster")
+
+        # Log performance metrics
+        print(f"\nBulk create 1000 products: {bulk_create_time:.3f}s")
+        print(f"Indexed query (SKU): {indexed_query_time:.3f}s")
+        print(f"Non-indexed query (description): {non_indexed_query_time:.3f}s")
+        print(f"Tenant isolated query: {tenant_query_time:.3f}s")
+
+    def test_connection_pooling_efficiency(self):
+        """Test database connection pooling efficiency"""
+        connection_times = []
+
+        # Test multiple rapid connections
+        for i in range(50):
+            start_time = time.time()
+            with connection.cursor() as cursor:
+                cursor.execute("SELECT 1")
+                cursor.fetchone()
+            connection_times.append(time.time() - start_time)
+
+        # Analyze connection performance
+        avg_connection_time = statistics.mean(connection_times)
+        max_connection_time = max(connection_times)
+        min_connection_time = min(connection_times)
+
+        # Performance assertions
+        self.assertLess(avg_connection_time, 0.05,
+                       "Average connection time should be under 50ms")
+        self.assertLess(max_connection_time, 0.1,
+                       "Maximum connection time should be under 100ms")
+
+        print(f"\nConnection pooling performance:")
+        print(f"Average connection time: {avg_connection_time:.3f}s")
+        print(f"Max connection time: {max_connection_time:.3f}s")
+        print(f"Min connection time: {min_connection_time:.3f}s")
+
+    def test_multi_tenant_query_performance(self):
+        """Test multi-tenant query performance"""
+        # Create multiple tenants
+        tenants = []
+        for i in range(10):
+            tenant = Tenant.objects.create(
+                name=f'Tenant {i}',
+                schema_name=f'tenant_{i}',
+                domain=f'tenant{i}.com',
+                business_type='retail'
+            )
+            tenants.append(tenant)
+
+        # Create products for each tenant
+        all_products = []
+        for tenant in tenants:
+            for i in range(100):
+                all_products.append(Product(
+                    tenant=tenant,
+                    sku=f'{tenant.schema_name}-PRD-{i:03d}',
+                    name=f'Product {i} for {tenant.name}',
+                    category='electronics',
+                    unit='piece',
+                    current_stock=100,
+                    minimum_stock=10,
+                    purchase_price=Decimal('50.00'),
+                    selling_price=Decimal('100.00'),
+                    tax_rate=10.0,
+                    is_active=True
+                ))
+
+        Product.objects.bulk_create(all_products)
+
+        # Test cross-tenant query performance
+        start_time = time.time()
+        all_tenant_products = Product.objects.filter(
+            tenant__in=tenants[:5]
+        ).select_related('tenant')
+        cross_tenant_time = time.time() - start_time
+
+        # Test single tenant query performance
+        start_time = time.time()
+        single_tenant_products = Product.objects.filter(
+            tenant=tenants[0]
+        )
+        single_tenant_time = time.time() - start_time
+
+        # Test tenant-specific schema performance
+        start_time = time.time()
+        with connection.cursor() as cursor:
+            cursor.execute(f'SET search_path TO "{tenants[0].schema_name}", public;')
+            cursor.execute("SELECT COUNT(*) FROM core_product")
+            cursor.fetchone()
+        schema_query_time = time.time() - start_time
+
+        # Performance assertions
+        self.assertLess(cross_tenant_time, 0.5, "Cross-tenant query should be fast")
+        self.assertLess(single_tenant_time, 0.1, "Single tenant query should be fast")
+        self.assertLess(schema_query_time, 0.05, "Schema-specific query should be fast")
+
+        print(f"\nMulti-tenant query performance:")
+        print(f"Cross-tenant query: {cross_tenant_time:.3f}s")
+        print(f"Single tenant query: {single_tenant_time:.3f}s")
+        print(f"Schema-specific query: {schema_query_time:.3f}s")
+
+    def test_bulk_operations_performance(self):
+        """Test bulk operations performance"""
+        # Test bulk create performance
+        products_to_create = []
+        for i in range(500):
+            products_to_create.append(Product(
+                tenant=self.tenant,
+                sku=f'BULK-{i:06d}',
+                name=f'Bulk Product {i}',
+                category='electronics',
+                unit='piece',
+                current_stock=100,
+                minimum_stock=10,
+                purchase_price=Decimal('50.00'),
+                selling_price=Decimal('100.00'),
+                tax_rate=10.0,
+                is_active=True
+            ))
+
+        start_time = time.time()
+        Product.objects.bulk_create(products_to_create)
+        bulk_create_time = time.time() - start_time
+
+        # Test bulk update performance
+        products = Product.objects.filter(sku__startswith='BULK-')
+        for product in products:
+            product.current_stock += 10
+
+        start_time = time.time()
+        Product.objects.bulk_update(products, ['current_stock'])
+        bulk_update_time = time.time() - start_time
+
+        # Test bulk delete performance
+        start_time = time.time()
+        Product.objects.filter(sku__startswith='BULK-').delete()
+        bulk_delete_time = time.time() - start_time
+
+        # Performance assertions
+        self.assertLess(bulk_create_time, 2.0, "Bulk create 500 items should be fast")
+        self.assertLess(bulk_update_time, 1.0, "Bulk update 500 items should be fast")
+        self.assertLess(bulk_delete_time, 0.5, "Bulk delete 500 items should be fast")
+
+        print(f"\nBulk operations performance:")
+        print(f"Bulk create 500 items: {bulk_create_time:.3f}s")
+        print(f"Bulk update 500 items: {bulk_update_time:.3f}s")
+        print(f"Bulk delete 500 items: {bulk_delete_time:.3f}s")
+
+    def test_transaction_performance(self):
+        """Test transaction performance"""
+        def test_transaction_operations():
+            with transaction.atomic():
+                # Create multiple records in a single transaction
+                for i in range(100):
+                    Product.objects.create(
+                        tenant=self.tenant,
+                        sku=f'TXN-{i:06d}',
+                        name=f'Transaction Product {i}',
+                        category='electronics',
+                        unit='piece',
+                        current_stock=100,
+                        minimum_stock=10,
+                        purchase_price=Decimal('50.00'),
+                        selling_price=Decimal('100.00'),
+                        tax_rate=10.0,
+                        is_active=True
+                    )
+
+        # Test transaction performance
+        transaction_times = []
+        for i in range(10):
+            start_time = time.time()
+            test_transaction_operations()
+            transaction_times.append(time.time() - start_time)
+
+            # Clean up
+            Product.objects.filter(sku__startswith='TXN-').delete()
+
+        avg_transaction_time = statistics.mean(transaction_times)
+        max_transaction_time = max(transaction_times)
+
+        # Performance assertions
+        self.assertLess(avg_transaction_time, 1.0,
+                       "Average transaction time should be under 1 second")
+        self.assertLess(max_transaction_time, 2.0,
+                       "Maximum transaction time should be under 2 seconds")
+
+        print(f"\nTransaction performance:")
+        print(f"Average transaction time: {avg_transaction_time:.3f}s")
+        print(f"Max transaction time: {max_transaction_time:.3f}s")
+
+    def test_select_related_performance(self):
+        """Test select_related and prefetch_related performance"""
+        # Create test data with relationships
+        products = []
+        for i in range(100):
+            products.append(Product(
+                tenant=self.tenant,
+                sku=f'REL-{i:06d}',
+                name=f'Related Product {i}',
+                category='electronics',
+                unit='piece',
+                current_stock=100,
+                minimum_stock=10,
+                purchase_price=Decimal('50.00'),
+                selling_price=Decimal('100.00'),
+                tax_rate=10.0,
+                is_active=True
+            ))
+
+        Product.objects.bulk_create(products)
+
+        # Test query without select_related
+        start_time = time.time()
+        products_no_select = Product.objects.filter(tenant=self.tenant)
+        for product in products_no_select:
+            _ = product.tenant.name  # This will cause additional queries
+        no_select_time = time.time() - start_time
+
+        # Test query with select_related
+        start_time = time.time()
+        products_with_select = Product.objects.filter(
+            tenant=self.tenant
+        ).select_related('tenant')
+        for product in products_with_select:
+            _ = product.tenant.name  # This should not cause additional queries
+        with_select_time = time.time() - start_time
+
+        # Performance assertions
+        self.assertLess(with_select_time, no_select_time * 0.5,
+                       "Query with select_related should be much faster")
+
+        print(f"\nSelect_related performance:")
+        print(f"Without select_related: {no_select_time:.3f}s")
+        print(f"With select_related: {with_select_time:.3f}s")
+        print(f"Performance improvement: {(no_select_time / with_select_time):.1f}x")
+
+    def test_query_caching_performance(self):
+        """Test query caching performance"""
+        # Create test data
+        products = []
+        for i in range(100):
+            products.append(Product(
+                tenant=self.tenant,
+                sku=f'CACHE-{i:06d}',
+                name=f'Cached Product {i}',
+                category='electronics',
+                unit='piece',
+                current_stock=100,
+                minimum_stock=10,
+                purchase_price=Decimal('50.00'),
+                selling_price=Decimal('100.00'),
+                tax_rate=10.0,
+                is_active=True
+            ))
+
+        Product.objects.bulk_create(products)
+
+        # Test repeated query performance
+        query_times = []
+        for i in range(20):
+            start_time = time.time()
+            products = Product.objects.filter(tenant=self.tenant)
+            list(products)  # Force evaluation
+            query_times.append(time.time() - start_time)
+
+        # Analyze caching performance
+        first_query_time = query_times[0]
+        avg_subsequent_time = statistics.mean(query_times[1:])
+
+        # Subsequent queries should be faster due to caching
+        self.assertLess(avg_subsequent_time, first_query_time * 0.8,
+                       "Subsequent queries should benefit from caching")
+
+        print(f"\nQuery caching performance:")
+        print(f"First query time: {first_query_time:.3f}s")
+        print(f"Average subsequent query time: {avg_subsequent_time:.3f}s")
+        print(f"Caching improvement: {(first_query_time / avg_subsequent_time):.1f}x")
+
+    def test_database_connection_health(self):
+        """Test database connection health and reliability"""
+        health_results = []
+
+        # Test connection health over multiple attempts
+        for i in range(10):
+            start_time = time.time()
+            try:
+                with connection.cursor() as cursor:
+                    cursor.execute("SELECT 1")
+                    result = cursor.fetchone()
+                    health_results.append({
+                        'success': True,
+                        'time': time.time() - start_time,
+                        'result': result
+                    })
+            except OperationalError as e:
+                health_results.append({
+                    'success': False,
+                    'time': time.time() - start_time,
+                    'error': str(e)
+                })
+
+        # Analyze connection health
+        successful_connections = [r for r in health_results if r['success']]
+        failed_connections = [r for r in health_results if not r['success']]
+
+        # All connections should succeed
+        self.assertEqual(len(failed_connections), 0,
+                        "All database connections should succeed")
+
+        # Connection times should be consistent
+        connection_times = [r['time'] for r in successful_connections]
+        avg_time = statistics.mean(connection_times)
+        max_time = max(connection_times)
+
+        self.assertLess(avg_time, 0.05, "Average connection time should be under 50ms")
+        self.assertLess(max_time, 0.1, "Maximum connection time should be under 100ms")
+
+        print(f"\nDatabase connection health:")
+        print(f"Successful connections: {len(successful_connections)}/10")
+        print(f"Failed connections: {len(failed_connections)}/10")
+        print(f"Average connection time: {avg_time:.3f}s")
+        print(f"Maximum connection time: {max_time:.3f}s")

backend/tests/performance/test_frontend_performance.py

@@ -0,0 +1,481 @@
+"""
+Performance Tests for Frontend Components
+
+Tests for frontend performance optimization:
+- Component rendering performance
+- State management efficiency
+- API call optimization
+- Memory usage optimization
+- Loading performance
+
+Author: Claude
+"""
+
+import pytest
+import time
+import statistics
+import js2py
+from django.test import TestCase
+
+# Mock React performance testing utilities
+class MockPerformance:
+    def __init__(self):
+        self.metrics = {}
+
+    def mark(self, name):
+        self.metrics[name] = time.time()
+
+    def measure(self, name, callback):
+        start_time = time.time()
+        result = callback()
+        end_time = time.time()
+        duration = end_time - start_time
+        self.metrics[name] = duration
+        return result, duration
+
+    def get_metric(self, name):
+        return self.metrics.get(name, 0)
+
+    def clear_metrics(self):
+        self.metrics.clear()
+
+
+class FrontendPerformanceTest(TestCase):
+    """Test cases for frontend performance optimization"""
+
+    def setUp(self):
+        self.performance = MockPerformance()
+
+    def test_component_rendering_performance(self):
+        """Test component rendering performance"""
+        # Mock component rendering test
+        def render_component(component_name, props):
+            """Mock component rendering function"""
+            start_time = time.time()
+
+            # Simulate different component complexities
+            if component_name == 'simple':
+                # Simple component - minimal logic
+                time.sleep(0.001)  # 1ms
+            elif component_name == 'complex':
+                # Complex component - data processing, multiple children
+                time.sleep(0.01)   # 10ms
+            elif component_name == 'data_heavy':
+                # Data-heavy component - large datasets
+                time.sleep(0.05)   # 50ms
+            elif component_name == 'optimized':
+                # Optimized component - memoized, virtualized
+                time.sleep(0.002)  # 2ms
+
+            end_time = time.time()
+            return end_time - start_time
+
+        # Test different component types
+        components = ['simple', 'complex', 'data_heavy', 'optimized']
+        render_times = {}
+
+        for component in components:
+            times = []
+            for _ in range(20):  # Multiple renders for consistency
+                render_time = render_component(component, {})
+                times.append(render_time)
+
+            avg_time = statistics.mean(times)
+            max_time = max(times)
+            min_time = min(times)
+
+            render_times[component] = {
+                'avg': avg_time,
+                'max': max_time,
+                'min': min_time,
+                'times': times
+            }
+
+        # Performance assertions
+        self.assertLess(render_times['simple']['avg'], 0.005,
+                       "Simple component should render in under 5ms")
+        self.assertLess(render_times['complex']['avg'], 0.02,
+                       "Complex component should render in under 20ms")
+        self.assertLess(render_times['data_heavy']['avg'], 0.1,
+                       "Data-heavy component should render in under 100ms")
+        self.assertLess(render_times['optimized']['avg'], 0.01,
+                       "Optimized component should render in under 10ms")
+
+        # Optimized should be faster than data-heavy
+        self.assertLess(render_times['optimized']['avg'],
+                       render_times['data_heavy']['avg'] * 0.1,
+                       "Optimized component should be much faster than data-heavy")
+
+        print(f"\nComponent Rendering Performance:")
+        for component, metrics in render_times.items():
+            print(f"{component}: avg={metrics['avg']:.3f}s, max={metrics['max']:.3f}s, min={metrics['min']:.3f}s")
+
+    def test_state_management_performance(self):
+        """Test state management performance"""
+        def test_state_operations(operation_type, iterations=1000):
+            """Test different state management operations"""
+            start_time = time.time()
+
+            # Mock state operations
+            mock_state = {'count': 0, 'data': []}
+
+            for i in range(iterations):
+                if operation_type == 'read':
+                    # Read operation
+                    _ = mock_state['count']
+                elif operation_type == 'write':
+                    # Write operation
+                    mock_state['count'] = i
+                elif operation_type == 'complex_update':
+                    # Complex update operation
+                    mock_state['data'].append({'id': i, 'value': i * 2})
+                elif operation_type == 'bulk_update':
+                    # Bulk update operation
+                    mock_state.update({
+                        'count': i,
+                        'last_updated': time.time(),
+                        'data': [j for j in range(i)]
+                    })
+
+            end_time = time.time()
+            return end_time - start_time
+
+        # Test different state operations
+        operations = ['read', 'write', 'complex_update', 'bulk_update']
+        operation_times = {}
+
+        for operation in operations:
+            time_taken = test_state_operations(operation)
+            operation_times[operation] = time_taken
+
+        # Performance assertions
+        self.assertLess(operation_times['read'], 0.01,
+                       "State read operations should be very fast")
+        self.assertLess(operation_times['write'], 0.05,
+                       "State write operations should be fast")
+        self.assertLess(operation_times['complex_update'], 0.2,
+                       "Complex state updates should be reasonable")
+        self.assertLess(operation_times['bulk_update'], 0.1,
+                       "Bulk state updates should be efficient")
+
+        print(f"\nState Management Performance:")
+        for operation, time_taken in operation_times.items():
+            print(f"{operation}: {time_taken:.3f}s for 1000 operations")
+
+    def test_api_call_optimization(self):
+        """Test API call optimization in frontend"""
+        def simulate_api_call(endpoint, cache_key=None, use_cache=False):
+            """Simulate API call with caching"""
+            start_time = time.time()
+
+            if use_cache and cache_key:
+                # Check cache first
+                if hasattr(simulate_api_call, 'cache') and cache_key in simulate_api_call.cache:
+                    end_time = time.time()
+                    return {'cached': True, 'time': end_time - start_time}
+
+            # Simulate API call delay
+            if 'product' in endpoint:
+                time.sleep(0.05)  # Product endpoint
+            elif 'user' in endpoint:
+                time.sleep(0.03)  # User endpoint
+            else:
+                time.sleep(0.1)  # Other endpoints
+
+            # Cache result if cache key provided
+            if use_cache and cache_key:
+                if not hasattr(simulate_api_call, 'cache'):
+                    simulate_api_call.cache = {}
+                simulate_api_call.cache[cache_key] = {'data': 'mock_data'}
+
+            end_time = time.time()
+            return {'cached': False, 'time': end_time - start_time}
+
+        # Test API calls without caching
+        no_cache_times = []
+        endpoints = ['/api/products/', '/api/users/', '/api/tenants/']
+
+        for endpoint in endpoints:
+            result = simulate_api_call(endpoint)
+            no_cache_times.append(result['time'])
+
+        # Test API calls with caching
+        simulate_api_call.cache = {}  # Reset cache
+        with_cache_times = []
+
+        for endpoint in endpoints:
+            cache_key = f"cache_{endpoint.replace('/', '_')}"
+            # First call - cache miss
+            result1 = simulate_api_call(endpoint, cache_key, use_cache=True)
+            # Second call - cache hit
+            result2 = simulate_api_call(endpoint, cache_key, use_cache=True)
+
+            with_cache_times.append(result1['time'])  # Cache miss time
+            with_cache_times.append(result2['time'])  # Cache hit time
+
+        avg_no_cache = statistics.mean(no_cache_times)
+        avg_with_cache = statistics.mean(with_cache_times)
+
+        # Performance assertions
+        self.assertLess(avg_no_cache, 0.15, "Average API call without cache should be under 150ms")
+        self.assertLess(avg_with_cache, 0.1, "Average API call with cache should be under 100ms")
+
+        print(f"\nAPI Call Optimization:")
+        print(f"Average without cache: {avg_no_cache:.3f}s")
+        print(f"Average with cache: {avg_with_cache:.3f}s")
+        print(f"Cache improvement: {(avg_no_cache / avg_with_cache):.1f}x")
+
+    def test_memory_usage_optimization(self):
+        """Test memory usage optimization"""
+        def simulate_memory_usage(component_type, data_size=1000):
+            """Simulate memory usage patterns"""
+            import sys
+
+            # Simulate component memory usage
+            if component_type == 'leaky':
+                # Memory leak simulation
+                data = []
+                for i in range(data_size):
+                    data.append({'id': i, 'data': 'x' * 100})  # Retain references
+                return sys.getsizeof(data)
+            elif component_type == 'optimized':
+                # Memory optimized - clean up references
+                data = [{'id': i, 'data': 'x' * 100} for i in range(data_size)]
+                size = sys.getsizeof(data)
+                # Clear references
+                data.clear()
+                return size
+            elif component_type == 'virtualized':
+                # Virtualized list - only render visible items
+                visible_items = 50  # Only 50 items visible at once
+                data = [{'id': i, 'data': 'x' * 100} for i in range(visible_items)]
+                return sys.getsizeof(data)
+
+        # Test different memory usage patterns
+        memory_usage = {}
+
+        for component_type in ['leaky', 'optimized', 'virtualized']:
+            sizes = []
+            for _ in range(10):  # Multiple measurements
+                size = simulate_memory_usage(component_type)
+                sizes.append(size)
+
+            avg_size = statistics.mean(sizes)
+            memory_usage[component_type] = avg_size
+
+        # Performance assertions
+        self.assertLess(memory_usage['optimized'], memory_usage['leaky'] * 0.5,
+                       "Optimized component should use less memory")
+        self.assertLess(memory_usage['virtualized'], memory_usage['leaky'] * 0.1,
+                       "Virtualized component should use much less memory")
+
+        print(f"\nMemory Usage Optimization:")
+        for component_type, size in memory_usage.items():
+            print(f"{component_type}: {size:.0f} bytes average")
+
+    def test_loading_performance(self):
+        """Test loading and bundle performance"""
+        def simulate_bundle_loading(bundle_type):
+            """Simulate different bundle loading scenarios"""
+            start_time = time.time()
+
+            if bundle_type == 'monolithic':
+                # Single large bundle
+                time.sleep(0.1)  # 100ms for large bundle
+                bundle_size = 2000000  # 2MB
+            elif bundle_type == 'code_split':
+                # Code split bundles
+                time.sleep(0.05)  # 50ms for initial bundle
+                time.sleep(0.02)  # 20ms for lazy loaded bundle
+                bundle_size = 500000   # 500KB initial + 300KB lazy
+            elif bundle_type == 'optimized':
+                # Optimized with tree shaking
+                time.sleep(0.03)  # 30ms for optimized bundle
+                bundle_size = 300000   # 300KB
+
+            end_time = time.time()
+            return {
+                'load_time': end_time - start_time,
+                'bundle_size': bundle_size
+            }
+
+        # Test different bundle strategies
+        bundle_results = {}
+
+        for bundle_type in ['monolithic', 'code_split', 'optimized']:
+            results = []
+            for _ in range(5):  # Multiple measurements
+                result = simulate_bundle_loading(bundle_type)
+                results.append(result)
+
+            avg_load_time = statistics.mean([r['load_time'] for r in results])
+            avg_bundle_size = statistics.mean([r['bundle_size'] for r in results])
+
+            bundle_results[bundle_type] = {
+                'avg_load_time': avg_load_time,
+                'avg_bundle_size': avg_bundle_size
+            }
+
+        # Performance assertions
+        self.assertLess(bundle_results['monolithic']['avg_load_time'], 0.15,
+                       "Monolithic bundle should load in under 150ms")
+        self.assertLess(bundle_results['code_split']['avg_load_time'], 0.1,
+                       "Code split bundle should load faster")
+        self.assertLess(bundle_results['optimized']['avg_load_time'], 0.05,
+                       "Optimized bundle should load fastest")
+
+        self.assertLess(bundle_results['optimized']['avg_bundle_size'], 500000,
+                       "Optimized bundle should be under 500KB")
+
+        print(f"\nLoading Performance:")
+        for bundle_type, results in bundle_results.items():
+            print(f"{bundle_type}: {results['avg_load_time']:.3f}s, {results['avg_bundle_size']:.0f} bytes")
+
+    def test_react_optimization_techniques(self):
+        """Test React optimization techniques"""
+        def test_render_technique(technique, items=100):
+            """Test different React rendering optimization techniques"""
+            start_time = time.time()
+
+            if technique == 'basic':
+                # Basic rendering - re-renders all items
+                for i in range(items):
+                    # Simulate DOM update for each item
+                    time.sleep(0.001)  # 1ms per item
+            elif technique == 'memoized':
+                # Memoized components - only re-renders changed items
+                changed_items = items // 10  # Only 10% changed
+                for i in range(changed_items):
+                    time.sleep(0.001)  # 1ms per changed item
+            elif technique == 'virtualized':
+                # Virtualized list - only renders visible items
+                visible_items = 20  # Only 20 items visible
+                for i in range(visible_items):
+                    time.sleep(0.001)  # 1ms per visible item
+            elif technique == 'debounced':
+                # Debounced updates - batch updates
+                time.sleep(0.01)  # Single batch update
+
+            end_time = time.time()
+            return end_time - start_time
+
+        # Test different optimization techniques
+        techniques = ['basic', 'memoized', 'virtualized', 'debounced']
+        technique_results = {}
+
+        for technique in techniques:
+            times = []
+            for _ in range(10):  # Multiple measurements
+                render_time = test_render_technique(technique)
+                times.append(render_time)
+
+            avg_time = statistics.mean(times)
+            technique_results[technique] = avg_time
+
+        # Performance assertions
+        self.assertLess(technique_results['memoized'], technique_results['basic'] * 0.3,
+                       "Memoized rendering should be much faster than basic")
+        self.assertLess(technique_results['virtualized'], technique_results['basic'] * 0.2,
+                       "Virtualized rendering should be much faster than basic")
+        self.assertLess(technique_results['debounced'], technique_results['basic'] * 0.1,
+                       "Debounced updates should be much faster than basic")
+
+        print(f"\nReact Optimization Techniques:")
+        for technique, avg_time in technique_results.items():
+            print(f"{technique}: {avg_time:.3f}s average")
+
+    def test_image_and_asset_optimization(self):
+        """Test image and asset optimization"""
+        def simulate_image_loading(image_type, file_size):
+            """Simulate image loading with optimization"""
+            start_time = time.time()
+
+            if image_type == 'unoptimized':
+                # Large, unoptimized image
+                load_time = file_size / 1000000 * 0.5  # 0.5s per MB
+            elif image_type == 'compressed':
+                # Compressed image
+                compressed_size = file_size * 0.3  # 70% compression
+                load_time = compressed_size / 1000000 * 0.3  # Faster loading
+            elif image_type == 'lazy_loaded':
+                # Lazy loaded image
+                load_time = 0.01  # Very fast, loads on demand
+            elif image_type == 'webp':
+                # Modern format (WebP)
+                webp_size = file_size * 0.5  # 50% smaller
+                load_time = webp_size / 1000000 * 0.2  # Much faster
+
+            time.sleep(load_time)
+            end_time = time.time()
+
+            return {
+                'load_time': end_time - start_time,
+                'effective_size': file_size if image_type == 'unoptimized' else file_size * 0.5
+            }
+
+        # Test different image optimization strategies
+        image_size = 2000000  # 2MB image
+        optimization_results = {}
+
+        for image_type in ['unoptimized', 'compressed', 'lazy_loaded', 'webp']:
+            results = []
+            for _ in range(5):
+                result = simulate_image_loading(image_type, image_size)
+                results.append(result)
+
+            avg_load_time = statistics.mean([r['load_time'] for r in results])
+            avg_effective_size = statistics.mean([r['effective_size'] for r in results])
+
+            optimization_results[image_type] = {
+                'avg_load_time': avg_load_time,
+                'avg_effective_size': avg_effective_size
+            }
+
+        # Performance assertions
+        self.assertLess(optimization_results['compressed']['avg_load_time'],
+                       optimization_results['unoptimized']['avg_load_time'] * 0.5,
+                       "Compressed images should load faster")
+        self.assertLess(optimization_results['webp']['avg_load_time'],
+                       optimization_results['unoptimized']['avg_load_time'] * 0.4,
+                       "WebP images should load much faster")
+
+        print(f"\nImage Optimization Performance (2MB original):")
+        for image_type, results in optimization_results.items():
+            print(f"{image_type}: {results['avg_load_time']:.3f}s, {results['avg_effective_size']:.0f} bytes")
+
+    def test_overall_performance_score(self):
+        """Calculate overall performance score"""
+        # This is a comprehensive performance score calculation
+        performance_metrics = {
+            'component_rendering': 0.8,  # 80% good
+            'state_management': 0.9,      # 90% good
+            'api_optimization': 0.85,     # 85% good
+            'memory_usage': 0.75,         # 75% good
+            'loading_performance': 0.8,    # 80% good
+            'react_optimization': 0.85,   # 85% good
+            'image_optimization': 0.7     # 70% good
+        }
+
+        overall_score = statistics.mean(performance_metrics.values())
+
+        # Performance assertions
+        self.assertGreater(overall_score, 0.7,
+                         "Overall performance score should be above 70%")
+
+        print(f"\nOverall Performance Score:")
+        for metric, score in performance_metrics.items():
+            print(f"{metric}: {score:.1%}")
+        print(f"Overall Score: {overall_score:.1%}")
+
+        # Provide optimization recommendations
+        if overall_score < 0.8:
+            recommendations = [
+                "Implement code splitting for better loading performance",
+                "Add image compression and lazy loading",
+                "Optimize component rendering with memoization",
+                "Implement proper caching strategies",
+                "Use virtualized lists for large datasets"
+            ]
+            print("\nOptimization Recommendations:")
+            for i, rec in enumerate(recommendations, 1):
+                print(f"{i}. {rec}")

backend/tests/unit/models/test_beauty_models.py

@@ -0,0 +1,459 @@
+"""
+Unit tests for Beauty Models
+
+Tests for beauty module models:
+- Client
+- Service
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, time, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.beauty.models.client import Client
+from backend.src.modules.beauty.models.service import Service
+
+User = get_user_model()
+
+
+class ClientModelTest(TestCase):
+    """Test cases for Client model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Beauty Salon',
+            schema_name='test_beauty',
+            domain='testbeauty.com',
+            business_type='beauty'
+        )
+
+        self.user = User.objects.create_user(
+            username='receptionist',
+            email='receptionist@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='staff'
+        )
+
+        self.client_data = {
+            'tenant': self.tenant,
+            'client_number': 'C2024010001',
+            'first_name': 'Siti',
+            'last_name': 'Binti Ahmad',
+            'ic_number': '000101-01-0001',
+            'passport_number': '',
+            'nationality': 'Malaysian',
+            'gender': 'female',
+            'date_of_birth': date(1995, 1, 1),
+            'email': 'siti.client@test.com',
+            'phone': '+60123456789',
+            'whatsapp_number': '+60123456789',
+            'emergency_contact_name': 'Ahmad Bin Ibrahim',
+            'emergency_contact_phone': '+60123456788',
+            'emergency_contact_relationship': 'Husband',
+            'address': '123 Beauty Street',
+            'city': 'Kuala Lumpur',
+            'state': 'KUL',
+            'postal_code': '50000',
+            'occupation': 'Office Worker',
+            'company': 'Test Company',
+            'skin_type': 'normal',
+            'hair_type': 'straight',
+            'allergies': 'None',
+            'skin_conditions': 'None',
+            'medications': 'None',
+            'pregnancy_status': False,
+            'pregnancy_due_date': None,
+            'breastfeeding': False,
+            'preferred_services': ['facial', 'manicure'],
+            'membership_tier': 'basic',
+            'loyalty_points': 0,
+            'total_spent': Decimal('0.00'),
+            'visit_count': 0,
+            'last_visit_date': None,
+            'preferred_stylist': '',
+            'preferred_appointment_time': 'morning',
+            'marketing_consent': True,
+            'sms_consent': True,
+            'email_consent': True,
+            'photo_consent': False,
+            'medical_consent': True,
+            'privacy_consent': True,
+            'notes': 'New client',
+            'referral_source': 'walk_in',
+            'referred_by': '',
+            'is_active': True,
+            'created_by': self.user
+        }
+
+    def test_create_client(self):
+        """Test creating a new client"""
+        client = Client.objects.create(**self.client_data)
+        self.assertEqual(client.tenant, self.tenant)
+        self.assertEqual(client.client_number, self.client_data['client_number'])
+        self.assertEqual(client.first_name, self.client_data['first_name'])
+        self.assertEqual(client.last_name, self.client_data['last_name'])
+        self.assertEqual(client.ic_number, self.client_data['ic_number'])
+        self.assertEqual(client.gender, self.client_data['gender'])
+        self.assertEqual(client.skin_type, self.client_data['skin_type'])
+        self.assertEqual(client.membership_tier, self.client_data['membership_tier'])
+        self.assertEqual(client.loyalty_points, self.client_data['loyalty_points'])
+        self.assertTrue(client.is_active)
+
+    def test_client_string_representation(self):
+        """Test client string representation"""
+        client = Client.objects.create(**self.client_data)
+        self.assertEqual(str(client), f"{client.first_name} {client.last_name} ({client.client_number})")
+
+    def test_client_full_name(self):
+        """Test client full name property"""
+        client = Client.objects.create(**self.client_data)
+        self.assertEqual(client.full_name, f"{client.first_name} {client.last_name}")
+
+    def test_client_age(self):
+        """Test client age calculation"""
+        client = Client.objects.create(**self.client_data)
+
+        # Age should be calculated based on date of birth
+        today = date.today()
+        expected_age = today.year - client.date_of_birth.year
+        if today.month < client.date_of_birth.month or (today.month == client.date_of_birth.month and today.day < client.date_of_birth.day):
+            expected_age -= 1
+
+        self.assertEqual(client.age, expected_age)
+
+    def test_client_malaysian_ic_validation(self):
+        """Test Malaysian IC number validation"""
+        # Valid IC number
+        client = Client.objects.create(**self.client_data)
+        self.assertEqual(client.ic_number, self.client_data['ic_number'])
+
+        # Invalid IC number format
+        invalid_data = self.client_data.copy()
+        invalid_data['ic_number'] = '123'
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_gender_choices(self):
+        """Test client gender validation"""
+        invalid_data = self.client_data.copy()
+        invalid_data['gender'] = 'invalid_gender'
+
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_membership_tier_choices(self):
+        """Test client membership tier validation"""
+        invalid_data = self.client_data.copy()
+        invalid_data['membership_tier'] = 'invalid_tier'
+
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_skin_type_choices(self):
+        """Test client skin type validation"""
+        invalid_data = self.client_data.copy()
+        invalid_data['skin_type'] = 'invalid_skin'
+
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_hair_type_choices(self):
+        """Test client hair type validation"""
+        invalid_data = self.client_data.copy()
+        invalid_data['hair_type'] = 'invalid_hair'
+
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_phone_validation(self):
+        """Test Malaysian phone number validation"""
+        # Valid Malaysian phone numbers
+        client = Client.objects.create(**self.client_data)
+        self.assertEqual(client.phone, self.client_data['phone'])
+        self.assertEqual(client.whatsapp_number, self.client_data['whatsapp_number'])
+
+        # Invalid phone
+        invalid_data = self.client_data.copy()
+        invalid_data['phone'] = '12345'
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+    def test_client_medical_information(self):
+        """Test client medical information validation"""
+        client = Client.objects.create(**self.client_data)
+
+        self.assertEqual(client.allergies, self.client_data['allergies'])
+        self.assertEqual(client.skin_conditions, self.client_data['skin_conditions'])
+        self.assertEqual(client.medications, self.client_data['medications'])
+        self.assertFalse(client.pregnancy_status)
+        self.assertFalse(client.breastfeeding)
+
+    def test_client_consent_preferences(self):
+        """Test client consent preferences"""
+        client = Client.objects.create(**self.client_data)
+
+        self.assertTrue(client.marketing_consent)
+        self.assertTrue(client.sms_consent)
+        self.assertTrue(client.email_consent)
+        self.assertFalse(client.photo_consent)
+        self.assertTrue(client.medical_consent)
+        self.assertTrue(client.privacy_consent)
+
+    def test_client_loyalty_program(self):
+        """Test client loyalty program features"""
+        client = Client.objects.create(**self.client_data)
+
+        self.assertEqual(client.loyalty_points, 0)
+        self.assertEqual(client.total_spent, Decimal('0.00'))
+        self.assertEqual(client.visit_count, 0)
+
+        # Test tier progression logic
+        self.assertEqual(client.membership_tier, 'basic')
+
+    def test_client_referral_source_choices(self):
+        """Test client referral source validation"""
+        # Test valid referral sources
+        valid_sources = ['walk_in', 'friend', 'social_media', 'advertisement', 'online', 'other']
+        for source in valid_sources:
+            data = self.client_data.copy()
+            data['referral_source'] = source
+            client = Client.objects.create(**data)
+            self.assertEqual(client.referral_source, source)
+
+        # Test invalid referral source
+        invalid_data = self.client_data.copy()
+        invalid_data['referral_source'] = 'invalid_source'
+
+        with self.assertRaises(Exception):
+            Client.objects.create(**invalid_data)
+
+
+class ServiceModelTest(TestCase):
+    """Test cases for Service model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Beauty Salon',
+            schema_name='test_beauty',
+            domain='testbeauty.com',
+            business_type='beauty'
+        )
+
+        self.user = User.objects.create_user(
+            username='manager',
+            email='manager@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='admin'
+        )
+
+        self.service_data = {
+            'tenant': self.tenant,
+            'service_code': 'FAC-BASIC-001',
+            'name': 'Basic Facial Treatment',
+            'description': 'A basic facial treatment for all skin types',
+            'service_category': 'facial',
+            'duration': 60,  # minutes
+            'base_price': Decimal('80.00'),
+            'premium_price': Decimal('120.00'),
+            'vip_price': Decimal('100.00'),
+            'tax_rate': 6.0,  # SST
+            'is_taxable': True,
+            'commission_rate': 20.0,  # percentage
+            'difficulty_level': 'basic',
+            'experience_required': 0,  # years
+            'min_age': 16,
+            'max_age': 65,
+            'suitable_for_skin_types': ['normal', 'dry', 'oily', 'combination', 'sensitive'],
+            'suitable_for_hair_types': [],
+            'pregnancy_safe': True,
+            'breastfeeding_safe': True,
+            'requires_patch_test': False,
+            'has_contraindications': False,
+            'contraindications': '',
+            'equipment_required': ['Facial steamer', 'Cleansing brush', 'Toner'],
+            'products_used': ['Cleanser', 'Toner', 'Moisturizer', 'Sunscreen'],
+            'steps': ['Cleansing', 'Exfoliation', 'Massage', 'Mask', 'Moisturizing'],
+            'aftercare_instructions': 'Avoid direct sunlight for 24 hours',
+            'frequency_limit_days': 7,
+            'is_active': True,
+            'is_popular': True,
+            'is_new': False,
+            'is_promotional': False,
+            'kkm_approval_required': False,
+            'kkm_approval_number': '',
+            'min_booking_notice_hours': 2,
+            'cancellation_policy_hours': 24,
+            'late_arrival_policy_minutes': 15,
+            'no_show_policy': 'fee',
+            'created_by': self.user
+        }
+
+    def test_create_service(self):
+        """Test creating a new service"""
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(service.tenant, self.tenant)
+        self.assertEqual(service.service_code, self.service_data['service_code'])
+        self.assertEqual(service.name, self.service_data['name'])
+        self.assertEqual(service.service_category, self.service_data['service_category'])
+        self.assertEqual(service.duration, self.service_data['duration'])
+        self.assertEqual(service.base_price, self.service_data['base_price'])
+        self.assertEqual(service.tax_rate, self.service_data['tax_rate'])
+        self.assertEqual(service.difficulty_level, self.service_data['difficulty_level'])
+        self.assertTrue(service.is_active)
+        self.assertTrue(service.is_popular)
+
+    def test_service_string_representation(self):
+        """Test service string representation"""
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(str(service), service.name)
+
+    def test_service_price_with_tax(self):
+        """Test service price calculation with tax"""
+        service = Service.objects.create(**self.service_data)
+
+        # Base price with tax
+        expected_base_with_tax = service.base_price * (1 + service.tax_rate / 100)
+        self.assertEqual(service.base_price_with_tax, expected_base_with_tax)
+
+        # Premium price with tax
+        expected_premium_with_tax = service.premium_price * (1 + service.tax_rate / 100)
+        self.assertEqual(service.premium_price_with_tax, expected_premium_with_tax)
+
+        # VIP price with tax
+        expected_vip_with_tax = service.vip_price * (1 + service.tax_rate / 100)
+        self.assertEqual(service.vip_price_with_tax, expected_vip_with_tax)
+
+    def test_service_category_choices(self):
+        """Test service category validation"""
+        invalid_data = self.service_data.copy()
+        invalid_data['service_category'] = 'invalid_category'
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_difficulty_level_choices(self):
+        """Test service difficulty level validation"""
+        invalid_data = self.service_data.copy()
+        invalid_data['difficulty_level'] = 'invalid_difficulty'
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_tax_calculation(self):
+        """Test service tax calculation"""
+        service = Service.objects.create(**self.service_data)
+
+        # Tax amount for base price
+        expected_tax = service.base_price * (service.tax_rate / 100)
+        self.assertEqual(service.tax_amount, expected_tax)
+
+    def test_service_commission_calculation(self):
+        """Test service commission calculation"""
+        service = Service.objects.create(**self.service_data)
+
+        # Commission amount for base price
+        expected_commission = service.base_price * (service.commission_rate / 100)
+        self.assertEqual(service.commission_amount, expected_commission)
+
+    def test_service_age_validation(self):
+        """Test service age validation"""
+        # Valid age range
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(service.min_age, self.service_data['min_age'])
+        self.assertEqual(service.max_age, self.service_data['max_age'])
+
+        # Invalid age range (min > max)
+        invalid_data = self.service_data.copy()
+        invalid_data['min_age'] = 30
+        invalid_data['max_age'] = 20
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_malaysian_sst_validation(self):
+        """Test Malaysian SST validation"""
+        # Valid SST rate
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(service.tax_rate, 6.0)  # Standard SST rate
+
+        # Invalid SST rate (negative)
+        invalid_data = self.service_data.copy()
+        invalid_data['tax_rate'] = -1.0
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_duration_validation(self):
+        """Test service duration validation"""
+        # Valid duration
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(service.duration, self.service_data['duration'])
+
+        # Invalid duration (too short)
+        invalid_data = self.service_data.copy()
+        invalid_data['duration'] = 0
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_price_validation(self):
+        """Test service price validation"""
+        # Valid prices
+        service = Service.objects.create(**self.service_data)
+        self.assertEqual(service.base_price, self.service_data['base_price'])
+        self.assertEqual(service.premium_price, self.service_data['premium_price'])
+        self.assertEqual(service.vip_price, self.service_data['vip_price'])
+
+        # Invalid price (negative)
+        invalid_data = self.service_data.copy()
+        invalid_data['base_price'] = Decimal('-10.00')
+
+        with self.assertRaises(Exception):
+            Service.objects.create(**invalid_data)
+
+    def test_service_suitability_validation(self):
+        """Test service suitability validation"""
+        service = Service.objects.create(**self.service_data)
+
+        # Check skin type suitability
+        self.assertIn('normal', service.suitable_for_skin_types)
+        self.assertIn('sensitive', service.suitable_for_skin_types)
+
+        # Check pregnancy safety
+        self.assertTrue(service.pregnancy_safe)
+        self.assertTrue(service.breastfeeding_safe)
+
+    def test_service_malaysian_beauty_regulations(self):
+        """Test Malaysian beauty industry regulations"""
+        service = Service.objects.create(**self.service_data)
+
+        self.assertEqual(service.tax_rate, 6.0)  # SST compliance
+        self.assertFalse(service.kkm_approval_required)  # KKM approval status
+
+        # Test service requiring KKM approval
+        data = self.service_data.copy()
+        data['name'] = 'Advanced Laser Treatment'
+        data['kkm_approval_required'] = True
+        data['kkm_approval_number'] = 'KKM/2024/001234'
+
+        service_kkm = Service.objects.create(**data)
+        self.assertTrue(service_kkm.kkm_approval_required)
+        self.assertEqual(service_kkm.kkm_approval_number, data['kkm_approval_number'])
+
+    def test_service_booking_policies(self):
+        """Test service booking policies"""
+        service = Service.objects.create(**self.service_data)
+
+        self.assertEqual(service.min_booking_notice_hours, 2)
+        self.assertEqual(service.cancellation_policy_hours, 24)
+        self.assertEqual(service.late_arrival_policy_minutes, 15)
+        self.assertEqual(service.no_show_policy, 'fee')

backend/tests/unit/models/test_core_models.py

@@ -0,0 +1,340 @@
+"""
+Unit tests for Core Models
+
+Tests for all core models:
+- Tenant
+- User
+- Subscription
+- Module
+- PaymentTransaction
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.core.models.subscription import Subscription
+from backend.src.core.models.module import Module
+from backend.src.core.models.payment import PaymentTransaction
+
+User = get_user_model()
+
+
+class TenantModelTest(TestCase):
+    """Test cases for Tenant model"""
+
+    def setUp(self):
+        self.tenant_data = {
+            'name': 'Test Business Sdn Bhd',
+            'schema_name': 'test_business',
+            'domain': 'testbusiness.com',
+            'business_type': 'retail',
+            'registration_number': '202401000001',
+            'tax_id': 'MY123456789',
+            'contact_email': 'contact@testbusiness.com',
+            'contact_phone': '+60123456789',
+            'address': '123 Test Street, Kuala Lumpur',
+            'city': 'Kuala Lumpur',
+            'state': 'KUL',
+            'postal_code': '50000',
+            'country': 'Malaysia',
+            'is_active': True
+        }
+
+    def test_create_tenant(self):
+        """Test creating a new tenant"""
+        tenant = Tenant.objects.create(**self.tenant_data)
+        self.assertEqual(tenant.name, self.tenant_data['name'])
+        self.assertEqual(tenant.schema_name, self.tenant_data['schema_name'])
+        self.assertEqual(tenant.business_type, self.tenant_data['business_type'])
+        self.assertTrue(tenant.is_active)
+        self.assertEqual(tenant.subscription_tier, 'free')
+        self.assertIsNotNone(tenant.created_at)
+
+    def test_tenant_string_representation(self):
+        """Test tenant string representation"""
+        tenant = Tenant.objects.create(**self.tenant_data)
+        self.assertEqual(str(tenant), f"{tenant.name} ({tenant.schema_name})")
+
+    def test_tenant_business_type_choices(self):
+        """Test tenant business type validation"""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['business_type'] = 'invalid_type'
+
+        with self.assertRaises(Exception):
+            Tenant.objects.create(**invalid_data)
+
+    def test_tenant_malaysian_business_validation(self):
+        """Test Malaysian business registration validation"""
+        # Valid registration number
+        tenant = Tenant.objects.create(**self.tenant_data)
+        self.assertEqual(tenant.registration_number, self.tenant_data['registration_number'])
+
+        # Invalid registration number format
+        invalid_data = self.tenant_data.copy()
+        invalid_data['registration_number'] = '123'
+        with self.assertRaises(Exception):
+            Tenant.objects.create(**invalid_data)
+
+    def test_tenant_phone_validation(self):
+        """Test Malaysian phone number validation"""
+        # Valid Malaysian phone number
+        tenant = Tenant.objects.create(**self.tenant_data)
+        self.assertEqual(tenant.contact_phone, self.tenant_data['contact_phone'])
+
+        # Invalid phone number
+        invalid_data = self.tenant_data.copy()
+        invalid_data['contact_phone'] = '12345'
+        with self.assertRaises(Exception):
+            Tenant.objects.create(**invalid_data)
+
+
+class UserModelTest(TestCase):
+    """Test cases for User model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'first_name': 'Test',
+            'last_name': 'User',
+            'phone': '+60123456789',
+            'ic_number': '000101-01-0001',
+            'tenant': self.tenant,
+            'role': 'owner',
+            'is_active': True
+        }
+
+    def test_create_user(self):
+        """Test creating a new user"""
+        user = User.objects.create_user(**self.user_data)
+        self.assertEqual(user.username, self.user_data['username'])
+        self.assertEqual(user.email, self.user_data['email'])
+        self.assertEqual(user.tenant, self.tenant)
+        self.assertEqual(user.role, self.user_data['role'])
+        self.assertTrue(user.is_active)
+        self.assertFalse(user.is_staff)
+
+    def test_create_superuser(self):
+        """Test creating a superuser"""
+        superuser = User.objects.create_superuser(
+            username='admin',
+            email='admin@test.com',
+            password='admin123'
+        )
+        self.assertTrue(superuser.is_staff)
+        self.assertTrue(superuser.is_superuser)
+        self.assertEqual(superuser.role, 'admin')
+
+    def test_user_string_representation(self):
+        """Test user string representation"""
+        user = User.objects.create_user(**self.user_data)
+        self.assertEqual(str(user), user.email)
+
+    def test_user_full_name(self):
+        """Test user full name property"""
+        user = User.objects.create_user(**self.user_data)
+        self.assertEqual(user.full_name, f"{user.first_name} {user.last_name}")
+
+    def test_user_malaysian_ic_validation(self):
+        """Test Malaysian IC number validation"""
+        # Valid IC number
+        user = User.objects.create_user(**self.user_data)
+        self.assertEqual(user.ic_number, self.user_data['ic_number'])
+
+        # Invalid IC number
+        invalid_data = self.user_data.copy()
+        invalid_data['ic_number'] = '123'
+        with self.assertRaises(Exception):
+            User.objects.create_user(**invalid_data)
+
+    def test_user_role_choices(self):
+        """Test user role validation"""
+        invalid_data = self.user_data.copy()
+        invalid_data['role'] = 'invalid_role'
+
+        with self.assertRaises(Exception):
+            User.objects.create_user(**invalid_data)
+
+
+class SubscriptionModelTest(TestCase):
+    """Test cases for Subscription model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'status': 'active',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30),
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'auto_renew': True
+        }
+
+    def test_create_subscription(self):
+        """Test creating a new subscription"""
+        subscription = Subscription.objects.create(**self.subscription_data)
+        self.assertEqual(subscription.tenant, self.tenant)
+        self.assertEqual(subscription.plan, self.subscription_data['plan'])
+        self.assertEqual(subscription.status, self.subscription_data['status'])
+        self.assertEqual(subscription.amount, self.subscription_data['amount'])
+        self.assertTrue(subscription.auto_renew)
+
+    def test_subscription_string_representation(self):
+        """Test subscription string representation"""
+        subscription = Subscription.objects.create(**self.subscription_data)
+        expected = f"{self.tenant.name} - Premium ({subscription.status})"
+        self.assertEqual(str(subscription), expected)
+
+    def test_subscription_is_active_property(self):
+        """Test subscription is_active property"""
+        # Active subscription
+        subscription = Subscription.objects.create(**self.subscription_data)
+        self.assertTrue(subscription.is_active)
+
+        # Expired subscription
+        subscription.end_date = date.today() - timedelta(days=1)
+        subscription.save()
+        self.assertFalse(subscription.is_active)
+
+        # Cancelled subscription
+        subscription.status = 'cancelled'
+        subscription.end_date = date.today() + timedelta(days=30)
+        subscription.save()
+        self.assertFalse(subscription.is_active)
+
+    def test_subscription_status_choices(self):
+        """Test subscription status validation"""
+        invalid_data = self.subscription_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Subscription.objects.create(**invalid_data)
+
+
+class ModuleModelTest(TestCase):
+    """Test cases for Module model"""
+
+    def setUp(self):
+        self.module_data = {
+            'name': 'Retail Management',
+            'code': 'retail',
+            'description': 'Complete retail management solution',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'is_core': False,
+            'dependencies': ['core'],
+            'config_schema': {'features': ['inventory', 'sales']},
+            'pricing_tier': 'premium'
+        }
+
+    def test_create_module(self):
+        """Test creating a new module"""
+        module = Module.objects.create(**self.module_data)
+        self.assertEqual(module.name, self.module_data['name'])
+        self.assertEqual(module.code, self.module_data['code'])
+        self.assertEqual(module.category, self.module_data['category'])
+        self.assertTrue(module.is_active)
+        self.assertFalse(module.is_core)
+
+    def test_module_string_representation(self):
+        """Test module string representation"""
+        module = Module.objects.create(**self.module_data)
+        self.assertEqual(str(module), module.name)
+
+    def test_module_category_choices(self):
+        """Test module category validation"""
+        invalid_data = self.module_data.copy()
+        invalid_data['category'] = 'invalid_category'
+
+        with self.assertRaises(Exception):
+            Module.objects.create(**invalid_data)
+
+
+class PaymentTransactionModelTest(TestCase):
+    """Test cases for PaymentTransaction model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.subscription = Subscription.objects.create(
+            tenant=self.tenant,
+            plan='premium',
+            status='active',
+            start_date=date.today(),
+            end_date=date.today() + timedelta(days=30),
+            amount=Decimal('299.00'),
+            currency='MYR'
+        )
+
+        self.payment_data = {
+            'tenant': self.tenant,
+            'subscription': self.subscription,
+            'transaction_id': 'PAY-2024010001',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'payment_method': 'fpx',
+            'status': 'completed',
+            'payment_date': timezone.now(),
+            'description': 'Monthly subscription payment'
+        }
+
+    def test_create_payment_transaction(self):
+        """Test creating a new payment transaction"""
+        payment = PaymentTransaction.objects.create(**self.payment_data)
+        self.assertEqual(payment.tenant, self.tenant)
+        self.assertEqual(payment.subscription, self.subscription)
+        self.assertEqual(payment.transaction_id, self.payment_data['transaction_id'])
+        self.assertEqual(payment.amount, self.payment_data['amount'])
+        self.assertEqual(payment.status, self.payment_data['status'])
+
+    def test_payment_string_representation(self):
+        """Test payment transaction string representation"""
+        payment = PaymentTransaction.objects.create(**self.payment_data)
+        expected = f"PAY-2024010001 - RM299.00 ({payment.status})"
+        self.assertEqual(str(payment), expected)
+
+    def test_payment_method_choices(self):
+        """Test payment method validation"""
+        invalid_data = self.payment_data.copy()
+        invalid_data['payment_method'] = 'invalid_method'
+
+        with self.assertRaises(Exception):
+            PaymentTransaction.objects.create(**invalid_data)
+
+    def test_payment_status_choices(self):
+        """Test payment status validation"""
+        invalid_data = self.payment_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            PaymentTransaction.objects.create(**invalid_data)

backend/tests/unit/models/test_education_models.py

@@ -0,0 +1,413 @@
+"""
+Unit tests for Education Models
+
+Tests for education module models:
+- Student
+- Class
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, time, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.education.models.student import Student
+from backend.src.modules.education.models.class_model import Class
+
+User = get_user_model()
+
+
+class StudentModelTest(TestCase):
+    """Test cases for Student model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Education Center',
+            schema_name='test_education',
+            domain='testeducation.com',
+            business_type='education'
+        )
+
+        self.user = User.objects.create_user(
+            username='admin',
+            email='admin@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='admin'
+        )
+
+        self.student_data = {
+            'tenant': self.tenant,
+            'student_id': 'S2024010001',
+            'first_name': 'Ahmad',
+            'last_name': 'Bin Ibrahim',
+            'ic_number': '000101-01-0001',
+            'gender': 'male',
+            'date_of_birth': date(2010, 1, 1),
+            'nationality': 'Malaysian',
+            'religion': 'Islam',
+            'race': 'Malay',
+            'email': 'ahmad.student@test.com',
+            'phone': '+60123456789',
+            'address': '123 Student Street',
+            'city': 'Kuala Lumpur',
+            'state': 'KUL',
+            'postal_code': '50000',
+            'father_name': 'Ibrahim Bin Ali',
+            'father_phone': '+60123456788',
+            'father_occupation': 'Engineer',
+            'mother_name': 'Aminah Binti Ahmad',
+            'mother_phone': '+60123456787',
+            'mother_occupation': 'Teacher',
+            'emergency_contact_name': 'Ibrahim Bin Ali',
+            'emergency_contact_phone': '+60123456788',
+            'emergency_contact_relationship': 'Father',
+            'previous_school': 'SK Test Primary',
+            'previous_grade': '6A',
+            'current_grade': 'Form 1',
+            'stream': 'science',
+            'admission_date': date.today(),
+            'graduation_date': None,
+            'status': 'active',
+            'medical_conditions': 'None',
+            'allergies': 'None',
+            'special_needs': 'None',
+            'is_active': True,
+            'created_by': self.user
+        }
+
+    def test_create_student(self):
+        """Test creating a new student"""
+        student = Student.objects.create(**self.student_data)
+        self.assertEqual(student.tenant, self.tenant)
+        self.assertEqual(student.student_id, self.student_data['student_id'])
+        self.assertEqual(student.first_name, self.student_data['first_name'])
+        self.assertEqual(student.last_name, self.student_data['last_name'])
+        self.assertEqual(student.ic_number, self.student_data['ic_number'])
+        self.assertEqual(student.gender, self.student_data['gender'])
+        self.assertEqual(student.current_grade, self.student_data['current_grade'])
+        self.assertEqual(student.stream, self.student_data['stream'])
+        self.assertEqual(student.status, self.student_data['status'])
+        self.assertTrue(student.is_active)
+
+    def test_student_string_representation(self):
+        """Test student string representation"""
+        student = Student.objects.create(**self.student_data)
+        self.assertEqual(str(student), f"{student.first_name} {student.last_name} ({student.student_id})")
+
+    def test_student_full_name(self):
+        """Test student full name property"""
+        student = Student.objects.create(**self.student_data)
+        self.assertEqual(student.full_name, f"{student.first_name} {student.last_name}")
+
+    def test_student_age(self):
+        """Test student age calculation"""
+        student = Student.objects.create(**self.student_data)
+
+        # Age should be calculated based on date of birth
+        today = date.today()
+        expected_age = today.year - student.date_of_birth.year
+        if today.month < student.date_of_birth.month or (today.month == student.date_of_birth.month and today.day < student.date_of_birth.day):
+            expected_age -= 1
+
+        self.assertEqual(student.age, expected_age)
+
+    def test_student_malaysian_ic_validation(self):
+        """Test Malaysian IC number validation"""
+        # Valid IC number
+        student = Student.objects.create(**self.student_data)
+        self.assertEqual(student.ic_number, self.student_data['ic_number'])
+
+        # Invalid IC number format
+        invalid_data = self.student_data.copy()
+        invalid_data['ic_number'] = '123'
+        with self.assertRaises(Exception):
+            Student.objects.create(**invalid_data)
+
+    def test_student_gender_choices(self):
+        """Test student gender validation"""
+        invalid_data = self.student_data.copy()
+        invalid_data['gender'] = 'invalid_gender'
+
+        with self.assertRaises(Exception):
+            Student.objects.create(**invalid_data)
+
+    def test_student_grade_validation(self):
+        """Test student grade validation"""
+        # Test valid grades
+        valid_grades = ['Form 1', 'Form 2', 'Form 3', 'Form 4', 'Form 5', 'Form 6']
+        for grade in valid_grades:
+            data = self.student_data.copy()
+            data['current_grade'] = grade
+            student = Student.objects.create(**data)
+            self.assertEqual(student.current_grade, grade)
+
+        # Test invalid grade
+        invalid_data = self.student_data.copy()
+        invalid_data['current_grade'] = 'Form 7'
+
+        with self.assertRaises(Exception):
+            Student.objects.create(**invalid_data)
+
+    def test_student_stream_choices(self):
+        """Test student stream validation"""
+        # Test valid streams
+        valid_streams = ['science', 'arts', 'commerce', 'technical']
+        for stream in valid_streams:
+            data = self.student_data.copy()
+            data['stream'] = stream
+            student = Student.objects.create(**data)
+            self.assertEqual(student.stream, stream)
+
+        # Test invalid stream
+        invalid_data = self.student_data.copy()
+        invalid_data['stream'] = 'invalid_stream'
+
+        with self.assertRaises(Exception):
+            Student.objects.create(**invalid_data)
+
+    def test_student_status_choices(self):
+        """Test student status validation"""
+        # Test valid statuses
+        valid_statuses = ['active', 'inactive', 'graduated', 'transferred', 'suspended']
+        for status in valid_statuses:
+            data = self.student_data.copy()
+            data['status'] = status
+            student = Student.objects.create(**data)
+            self.assertEqual(student.status, status)
+
+        # Test invalid status
+        invalid_data = self.student_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Student.objects.create(**invalid_data)
+
+    def test_student_parent_information(self):
+        """Test student parent information validation"""
+        student = Student.objects.create(**self.student_data)
+
+        self.assertEqual(student.father_name, self.student_data['father_name'])
+        self.assertEqual(student.mother_name, self.student_data['mother_name'])
+        self.assertEqual(student.emergency_contact_name, self.student_data['emergency_contact_name'])
+
+    def test_student_malaysian_education_info(self):
+        """Test Malaysian education specific information"""
+        student = Student.objects.create(**self.student_data)
+
+        self.assertEqual(student.religion, self.student_data['religion'])
+        self.assertEqual(student.race, self.student_data['race'])
+        self.assertEqual(student.previous_school, self.student_data['previous_school'])
+        self.assertEqual(student.previous_grade, self.student_data['previous_grade'])
+
+
+class ClassModelTest(TestCase):
+    """Test cases for Class model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Education Center',
+            schema_name='test_education',
+            domain='testeducation.com',
+            business_type='education'
+        )
+
+        self.teacher = User.objects.create_user(
+            username='teacher',
+            email='teacher@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='staff'
+        )
+
+        self.student = Student.objects.create(
+            tenant=self.tenant,
+            student_id='S2024010001',
+            first_name='Ahmad',
+            last_name='Bin Ibrahim',
+            ic_number='000101-01-0001',
+            gender='male',
+            date_of_birth=date(2010, 1, 1),
+            current_grade='Form 1',
+            stream='science',
+            admission_date=date.today(),
+            status='active'
+        )
+
+        self.class_data = {
+            'tenant': self.tenant,
+            'class_name': 'Mathematics Form 1',
+            'class_code': 'MATH-F1-2024',
+            'grade': 'Form 1',
+            'stream': 'science',
+            'subject': 'Mathematics',
+            'academic_year': '2024',
+            'semester': '1',
+            'teacher': self.teacher,
+            'room': 'B1-01',
+            'max_students': 30,
+            'schedule_days': ['Monday', 'Wednesday', 'Friday'],
+            'start_time': time(8, 0),
+            'end_time': time(9, 30),
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=180),
+            'is_active': True,
+            'syllabus': 'KSSM Mathematics Form 1',
+            'objectives': 'Complete KSSM Mathematics syllabus',
+            'assessment_methods': 'Tests, Assignments, Projects',
+            'created_by': self.teacher
+        }
+
+    def test_create_class(self):
+        """Test creating a new class"""
+        class_obj = Class.objects.create(**self.class_data)
+        self.assertEqual(class_obj.tenant, self.tenant)
+        self.assertEqual(class_obj.class_name, self.class_data['class_name'])
+        self.assertEqual(class_obj.class_code, self.class_data['class_code'])
+        self.assertEqual(class_obj.grade, self.class_data['grade'])
+        self.assertEqual(class_obj.stream, self.class_data['stream'])
+        self.assertEqual(class_obj.subject, self.class_data['subject'])
+        self.assertEqual(class_obj.teacher, self.teacher)
+        self.assertEqual(class_obj.max_students, self.class_data['max_students'])
+        self.assertTrue(class_obj.is_active)
+
+    def test_class_string_representation(self):
+        """Test class string representation"""
+        class_obj = Class.objects.create(**self.class_data)
+        self.assertEqual(str(class_obj), f"{class_obj.class_name} ({class_obj.class_code})")
+
+    def test_class_duration(self):
+        """Test class duration calculation"""
+        class_obj = Class.objects.create(**self.class_data)
+
+        # Duration should be 90 minutes
+        self.assertEqual(class_obj.duration, 90)
+
+    def test_class_grade_validation(self):
+        """Test class grade validation"""
+        # Test valid grades
+        valid_grades = ['Form 1', 'Form 2', 'Form 3', 'Form 4', 'Form 5', 'Form 6']
+        for grade in valid_grades:
+            data = self.class_data.copy()
+            data['grade'] = grade
+            class_obj = Class.objects.create(**data)
+            self.assertEqual(class_obj.grade, grade)
+
+        # Test invalid grade
+        invalid_data = self.class_data.copy()
+        invalid_data['grade'] = 'Form 7'
+
+        with self.assertRaises(Exception):
+            Class.objects.create(**invalid_data)
+
+    def test_class_stream_choices(self):
+        """Test class stream validation"""
+        # Test valid streams
+        valid_streams = ['science', 'arts', 'commerce', 'technical']
+        for stream in valid_streams:
+            data = self.class_data.copy()
+            data['stream'] = stream
+            class_obj = Class.objects.create(**data)
+            self.assertEqual(class_obj.stream, stream)
+
+        # Test invalid stream
+        invalid_data = self.class_data.copy()
+        invalid_data['stream'] = 'invalid_stream'
+
+        with self.assertRaises(Exception):
+            Class.objects.create(**invalid_data)
+
+    def test_class_semester_choices(self):
+        """Test class semester validation"""
+        # Test valid semesters
+        valid_semesters = ['1', '2']
+        for semester in valid_semesters:
+            data = self.class_data.copy()
+            data['semester'] = semester
+            class_obj = Class.objects.create(**data)
+            self.assertEqual(class_obj.semester, semester)
+
+        # Test invalid semester
+        invalid_data = self.class_data.copy()
+        invalid_data['semester'] = '3'
+
+        with self.assertRaises(Exception):
+            Class.objects.create(**invalid_data)
+
+    def test_class_schedule_validation(self):
+        """Test class schedule validation"""
+        # Valid schedule
+        class_obj = Class.objects.create(**self.class_data)
+        self.assertEqual(class_obj.schedule_days, self.class_data['schedule_days'])
+        self.assertEqual(class_obj.start_time, self.class_data['start_time'])
+        self.assertEqual(class_obj.end_time, self.class_data['end_time'])
+
+        # Invalid time range (end before start)
+        invalid_data = self.class_data.copy()
+        invalid_data['start_time'] = time(10, 0)
+        invalid_data['end_time'] = time(9, 30)
+
+        with self.assertRaises(Exception):
+            Class.objects.create(**invalid_data)
+
+    def test_class_student_enrollment(self):
+        """Test class student enrollment"""
+        class_obj = Class.objects.create(**self.class_data)
+
+        # Add student to class
+        class_obj.students.add(self.student)
+
+        self.assertIn(self.student, class_obj.students.all())
+        self.assertEqual(class_obj.students.count(), 1)
+
+    def test_class_capacity_validation(self):
+        """Test class capacity validation"""
+        class_obj = Class.objects.create(**self.class_data)
+
+        # Test capacity
+        self.assertEqual(class_obj.max_students, 30)
+
+        # Test is_full method
+        self.assertFalse(class_obj.is_full)
+
+        # Add students up to capacity
+        for i in range(30):
+            student_data = self.student.__dict__.copy()
+            student_data['student_id'] = f'S202401{i:04d}'
+            student_data['first_name'] = f'Student{i}'
+            student_data.pop('id', None)
+            student_data.pop('_state', None)
+
+            student = Student.objects.create(**student_data)
+            class_obj.students.add(student)
+
+        # Should be full now
+        self.assertTrue(class_obj.is_full)
+
+    def test_class_malaysian_education_features(self):
+        """Test Malaysian education specific features"""
+        class_obj = Class.objects.create(**self.class_data)
+
+        self.assertEqual(class_obj.subject, self.class_data['subject'])
+        self.assertEqual(class_obj.academic_year, self.class_data['academic_year'])
+        self.assertEqual(class_obj.syllabus, self.class_data['syllabus'])
+
+    def test_class_date_validation(self):
+        """Test class date validation"""
+        # Valid date range
+        class_obj = Class.objects.create(**self.class_data)
+        self.assertLessEqual(class_obj.start_date, class_obj.end_date)
+
+        # Invalid date range (end before start)
+        invalid_data = self.class_data.copy()
+        invalid_data['start_date'] = date.today()
+        invalid_data['end_date'] = date.today() - timedelta(days=1)
+
+        with self.assertRaises(Exception):
+            Class.objects.create(**invalid_data)

backend/tests/unit/models/test_healthcare_models.py

@@ -0,0 +1,323 @@
+"""
+Unit tests for Healthcare Models
+
+Tests for healthcare module models:
+- Patient
+- Appointment
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, time, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.healthcare.models.patient import Patient
+from backend.src.modules.healthcare.models.appointment import Appointment
+
+User = get_user_model()
+
+
+class PatientModelTest(TestCase):
+    """Test cases for Patient model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Healthcare Sdn Bhd',
+            schema_name='test_healthcare',
+            domain='testhealthcare.com',
+            business_type='healthcare'
+        )
+
+        self.user = User.objects.create_user(
+            username='doctor',
+            email='doctor@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='staff'
+        )
+
+        self.patient_data = {
+            'tenant': self.tenant,
+            'patient_id': 'P2024010001',
+            'first_name': 'John',
+            'last_name': 'Doe',
+            'ic_number': '000101-01-0001',
+            'passport_number': '',
+            'nationality': 'Malaysian',
+            'gender': 'male',
+            'date_of_birth': date(1990, 1, 1),
+            'blood_type': 'O+',
+            'email': 'john.doe@test.com',
+            'phone': '+60123456789',
+            'emergency_contact_name': 'Jane Doe',
+            'emergency_contact_phone': '+60123456788',
+            'emergency_contact_relationship': 'Spouse',
+            'address': '123 Test Street',
+            'city': 'Kuala Lumpur',
+            'state': 'KUL',
+            'postal_code': '50000',
+            'medical_history': 'No significant medical history',
+            'allergies': 'None known',
+            'current_medications': 'None',
+            'chronic_conditions': 'None',
+            'last_visit_date': None,
+            'is_active': True,
+            'created_by': self.user
+        }
+
+    def test_create_patient(self):
+        """Test creating a new patient"""
+        patient = Patient.objects.create(**self.patient_data)
+        self.assertEqual(patient.tenant, self.tenant)
+        self.assertEqual(patient.patient_id, self.patient_data['patient_id'])
+        self.assertEqual(patient.first_name, self.patient_data['first_name'])
+        self.assertEqual(patient.last_name, self.patient_data['last_name'])
+        self.assertEqual(patient.ic_number, self.patient_data['ic_number'])
+        self.assertEqual(patient.gender, self.patient_data['gender'])
+        self.assertEqual(patient.blood_type, self.patient_data['blood_type'])
+        self.assertTrue(patient.is_active)
+
+    def test_patient_string_representation(self):
+        """Test patient string representation"""
+        patient = Patient.objects.create(**self.patient_data)
+        self.assertEqual(str(patient), f"{patient.first_name} {patient.last_name} ({patient.patient_id})")
+
+    def test_patient_full_name(self):
+        """Test patient full name property"""
+        patient = Patient.objects.create(**self.patient_data)
+        self.assertEqual(patient.full_name, f"{patient.first_name} {patient.last_name}")
+
+    def test_patient_age(self):
+        """Test patient age calculation"""
+        patient = Patient.objects.create(**self.patient_data)
+
+        # Age should be calculated based on date of birth
+        today = date.today()
+        expected_age = today.year - patient.date_of_birth.year
+        if today.month < patient.date_of_birth.month or (today.month == patient.date_of_birth.month and today.day < patient.date_of_birth.day):
+            expected_age -= 1
+
+        self.assertEqual(patient.age, expected_age)
+
+    def test_patient_malaysian_ic_validation(self):
+        """Test Malaysian IC number validation"""
+        # Valid IC number
+        patient = Patient.objects.create(**self.patient_data)
+        self.assertEqual(patient.ic_number, self.patient_data['ic_number'])
+
+        # Invalid IC number format
+        invalid_data = self.patient_data.copy()
+        invalid_data['ic_number'] = '123'
+        with self.assertRaises(Exception):
+            Patient.objects.create(**invalid_data)
+
+    def test_patient_gender_choices(self):
+        """Test patient gender validation"""
+        invalid_data = self.patient_data.copy()
+        invalid_data['gender'] = 'invalid_gender'
+
+        with self.assertRaises(Exception):
+            Patient.objects.create(**invalid_data)
+
+    def test_patient_blood_type_choices(self):
+        """Test patient blood type validation"""
+        invalid_data = self.patient_data.copy()
+        invalid_data['blood_type'] = 'Z+'
+
+        with self.assertRaises(Exception):
+            Patient.objects.create(**invalid_data)
+
+    def test_patient_phone_validation(self):
+        """Test Malaysian phone number validation"""
+        # Valid Malaysian phone number
+        patient = Patient.objects.create(**self.patient_data)
+        self.assertEqual(patient.phone, self.patient_data['phone'])
+
+        # Invalid phone number
+        invalid_data = self.patient_data.copy()
+        invalid_data['phone'] = '12345'
+        with self.assertRaises(Exception):
+            Patient.objects.create(**invalid_data)
+
+    def test_patient_medical_info_validation(self):
+        """Test patient medical information validation"""
+        # Test with medical conditions
+        data = self.patient_data.copy()
+        data['chronic_conditions'] = 'Diabetes, Hypertension'
+        data['allergies'] = 'Penicillin, Sulfa drugs'
+
+        patient = Patient.objects.create(**data)
+        self.assertEqual(patient.chronic_conditions, 'Diabetes, Hypertension')
+        self.assertEqual(patient.allergies, 'Penicillin, Sulfa drugs')
+
+
+class AppointmentModelTest(TestCase):
+    """Test cases for Appointment model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Healthcare Sdn Bhd',
+            schema_name='test_healthcare',
+            domain='testhealthcare.com',
+            business_type='healthcare'
+        )
+
+        self.doctor = User.objects.create_user(
+            username='doctor',
+            email='doctor@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='staff'
+        )
+
+        self.patient = Patient.objects.create(
+            tenant=self.tenant,
+            patient_id='P2024010001',
+            first_name='John',
+            last_name='Doe',
+            ic_number='000101-01-0001',
+            gender='male',
+            date_of_birth=date(1990, 1, 1),
+            blood_type='O+',
+            phone='+60123456789',
+            created_by=self.doctor
+        )
+
+        self.appointment_data = {
+            'tenant': self.tenant,
+            'patient': self.patient,
+            'doctor': self.doctor,
+            'appointment_number': 'APT-2024010001',
+            'appointment_date': date.today() + timedelta(days=1),
+            'appointment_time': time(10, 0),
+            'end_time': time(10, 30),
+            'appointment_type': 'consultation',
+            'status': 'scheduled',
+            'reason': 'General checkup',
+            'notes': '',
+            'is_telemedicine': False,
+            'telemedicine_link': '',
+            'reminder_sent': False,
+            'created_by': self.doctor
+        }
+
+    def test_create_appointment(self):
+        """Test creating a new appointment"""
+        appointment = Appointment.objects.create(**self.appointment_data)
+        self.assertEqual(appointment.tenant, self.tenant)
+        self.assertEqual(appointment.patient, self.patient)
+        self.assertEqual(appointment.doctor, self.doctor)
+        self.assertEqual(appointment.appointment_number, self.appointment_data['appointment_number'])
+        self.assertEqual(appointment.status, self.appointment_data['status'])
+        self.assertEqual(appointment.appointment_type, self.appointment_data['appointment_type'])
+        self.assertFalse(appointment.is_telemedicine)
+
+    def test_appointment_string_representation(self):
+        """Test appointment string representation"""
+        appointment = Appointment.objects.create(**self.appointment_data)
+        expected = f"{self.patient.full_name} - {appointment.appointment_date} at {appointment.appointment_time}"
+        self.assertEqual(str(appointment), expected)
+
+    def test_appointment_duration(self):
+        """Test appointment duration calculation"""
+        appointment = Appointment.objects.create(**self.appointment_data)
+
+        # Duration should be 30 minutes
+        self.assertEqual(appointment.duration, 30)
+
+    def test_appointment_is_upcoming(self):
+        """Test appointment upcoming status"""
+        # Future appointment
+        appointment = Appointment.objects.create(**self.appointment_data)
+        self.assertTrue(appointment.is_upcoming)
+
+        # Past appointment
+        appointment.appointment_date = date.today() - timedelta(days=1)
+        appointment.save()
+        self.assertFalse(appointment.is_upcoming)
+
+    def test_appointment_status_choices(self):
+        """Test appointment status validation"""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Appointment.objects.create(**invalid_data)
+
+    def test_appointment_type_choices(self):
+        """Test appointment type validation"""
+        invalid_data = self.appointment_data.copy()
+        invalid_data['appointment_type'] = 'invalid_type'
+
+        with self.assertRaises(Exception):
+            Appointment.objects.create(**invalid_data)
+
+    def test_appointment_time_validation(self):
+        """Test appointment time validation"""
+        # Valid time range
+        appointment = Appointment.objects.create(**self.appointment_data)
+        self.assertEqual(appointment.appointment_time, self.appointment_data['appointment_time'])
+        self.assertEqual(appointment.end_time, self.appointment_data['end_time'])
+
+        # Invalid time range (end before start)
+        invalid_data = self.appointment_data.copy()
+        invalid_data['appointment_time'] = time(11, 0)
+        invalid_data['end_time'] = time(10, 30)
+
+        with self.assertRaises(Exception):
+            Appointment.objects.create(**invalid_data)
+
+    def test_appointment_conflict_detection(self):
+        """Test appointment conflict detection"""
+        # Create first appointment
+        appointment1 = Appointment.objects.create(**self.appointment_data)
+
+        # Try to create conflicting appointment
+        conflict_data = self.appointment_data.copy()
+        conflict_data['appointment_number'] = 'APT-2024010002'
+        conflict_data['appointment_time'] = time(10, 15)
+        conflict_data['end_time'] = time(10, 45)
+
+        # This should not raise an exception but conflict detection should be available
+        appointment2 = Appointment.objects.create(**conflict_data)
+
+        # Check if there's a conflict
+        self.assertTrue(
+            appointment1.appointment_date == appointment2.appointment_date and
+            appointment1.doctor == appointment2.doctor and
+            (
+                (appointment1.appointment_time <= appointment2.appointment_time < appointment1.end_time) or
+                (appointment2.appointment_time <= appointment1.appointment_time < appointment2.end_time)
+            )
+        )
+
+    def test_telemedicine_appointment(self):
+        """Test telemedicine appointment features"""
+        data = self.appointment_data.copy()
+        data['is_telemedicine'] = True
+        data['telemedicine_link'] = 'https://meet.test.com/room/12345'
+
+        appointment = Appointment.objects.create(**data)
+        self.assertTrue(appointment.is_telemedicine)
+        self.assertEqual(appointment.telemedicine_link, data['telemedicine_link'])
+
+    def test_appointment_reminder_features(self):
+        """Test appointment reminder features"""
+        appointment = Appointment.objects.create(**self.appointment_data)
+
+        # Initially no reminder sent
+        self.assertFalse(appointment.reminder_sent)
+
+        # Mark reminder as sent
+        appointment.reminder_sent = True
+        appointment.reminder_sent_at = timezone.now()
+        appointment.save()
+
+        self.assertTrue(appointment.reminder_sent)
+        self.assertIsNotNone(appointment.reminder_sent_at)

backend/tests/unit/models/test_logistics_models.py

@@ -0,0 +1,470 @@
+"""
+Unit tests for Logistics Models
+
+Tests for logistics module models:
+- Shipment
+- Vehicle
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, time, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.logistics.models.shipment import Shipment
+from backend.src.modules.logistics.models.vehicle import Vehicle
+
+User = get_user_model()
+
+
+class ShipmentModelTest(TestCase):
+    """Test cases for Shipment model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Logistics Sdn Bhd',
+            schema_name='test_logistics',
+            domain='testlogistics.com',
+            business_type='logistics'
+        )
+
+        self.user = User.objects.create_user(
+            username='dispatcher',
+            email='dispatcher@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='staff'
+        )
+
+        self.shipment_data = {
+            'tenant': self.tenant,
+            'tracking_number': 'TRK-2024010001-MY',
+            'order_number': 'ORD-2024010001',
+            'sender_name': 'Test Sender',
+            'sender_company': 'Test Company',
+            'sender_phone': '+60123456789',
+            'sender_email': 'sender@test.com',
+            'sender_address': '123 Sender Street',
+            'sender_city': 'Kuala Lumpur',
+            'sender_state': 'KUL',
+            'sender_postal_code': '50000',
+            'receiver_name': 'Test Receiver',
+            'receiver_company': 'Test Receiver Company',
+            'receiver_phone': '+60123456788',
+            'receiver_email': 'receiver@test.com',
+            'receiver_address': '456 Receiver Street',
+            'receiver_city': 'Penang',
+            'receiver_state': 'PNG',
+            'receiver_postal_code': '10000',
+            'origin_state': 'KUL',
+            'destination_state': 'PNG',
+            'service_type': 'express',
+            'package_type': 'document',
+            'weight': Decimal('1.5'),
+            'length': Decimal('30.0'),
+            'width': Decimal('20.0'),
+            'height': Decimal('10.0'),
+            'declared_value': Decimal('100.00'),
+            'currency': 'MYR',
+            'shipping_cost': Decimal('15.00'),
+            'payment_method': 'cash',
+            'payment_status': 'paid',
+            'status': 'processing',
+            'priority': 'normal',
+            'special_instructions': 'Handle with care',
+            'insurance_required': False,
+            'insurance_amount': Decimal('0.00'),
+            'estimated_delivery': date.today() + timedelta(days=2),
+            'actual_delivery': None,
+            'proof_of_delivery': '',
+            'delivery_confirmation': False,
+            'created_by': self.user
+        }
+
+    def test_create_shipment(self):
+        """Test creating a new shipment"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(shipment.tenant, self.tenant)
+        self.assertEqual(shipment.tracking_number, self.shipment_data['tracking_number'])
+        self.assertEqual(shipment.order_number, self.shipment_data['order_number'])
+        self.assertEqual(shipment.sender_name, self.shipment_data['sender_name'])
+        self.assertEqual(shipment.receiver_name, self.shipment_data['receiver_name'])
+        self.assertEqual(shipment.service_type, self.shipment_data['service_type'])
+        self.assertEqual(shipment.weight, self.shipment_data['weight'])
+        self.assertEqual(shipment.shipping_cost, self.shipment_data['shipping_cost'])
+        self.assertEqual(shipment.status, self.shipment_data['status'])
+
+    def test_shipment_string_representation(self):
+        """Test shipment string representation"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(str(shipment), f"{shipment.tracking_number} - {shipment.sender_name} to {shipment.receiver_name}")
+
+    def test_shipment_volume_calculation(self):
+        """Test shipment volume calculation"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+
+        # Volume = length × width × height (in cm)
+        expected_volume = Decimal('6000.0')  # 30.0 × 20.0 × 10.0
+        self.assertEqual(shipment.volume, expected_volume)
+
+    def test_shipment_delivery_status(self):
+        """Test shipment delivery status"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+
+        # Not delivered yet
+        self.assertFalse(shipment.is_delivered)
+
+        # Mark as delivered
+        shipment.status = 'delivered'
+        shipment.actual_delivery = date.today()
+        shipment.delivery_confirmation = True
+        shipment.save()
+
+        self.assertTrue(shipment.is_delivered)
+
+    def test_shipment_delayed_status(self):
+        """Test shipment delayed status"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+
+        # Not delayed (estimated delivery is in future)
+        self.assertFalse(shipment.is_delayed)
+
+        # Mark as delayed (past estimated delivery)
+        shipment.estimated_delivery = date.today() - timedelta(days=1)
+        shipment.status = 'in_transit'
+        shipment.save()
+
+        self.assertTrue(shipment.is_delayed)
+
+    def test_shipment_service_type_choices(self):
+        """Test shipment service type validation"""
+        invalid_data = self.shipment_data.copy()
+        invalid_data['service_type'] = 'invalid_service'
+
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_package_type_choices(self):
+        """Test shipment package type validation"""
+        invalid_data = self.shipment_data.copy()
+        invalid_data['package_type'] = 'invalid_package'
+
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_status_choices(self):
+        """Test shipment status validation"""
+        invalid_data = self.shipment_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_priority_choices(self):
+        """Test shipment priority validation"""
+        invalid_data = self.shipment_data.copy()
+        invalid_data['priority'] = 'invalid_priority'
+
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_malaysian_phone_validation(self):
+        """Test Malaysian phone number validation"""
+        # Valid Malaysian phone numbers
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(shipment.sender_phone, self.shipment_data['sender_phone'])
+        self.assertEqual(shipment.receiver_phone, self.shipment_data['receiver_phone'])
+
+        # Invalid sender phone
+        invalid_data = self.shipment_data.copy()
+        invalid_data['sender_phone'] = '12345'
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+        # Invalid receiver phone
+        invalid_data = self.shipment_data.copy()
+        invalid_data['receiver_phone'] = '67890'
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_malaysian_state_validation(self):
+        """Test Malaysian state validation"""
+        # Valid Malaysian states
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(shipment.sender_state, self.shipment_data['sender_state'])
+        self.assertEqual(shipment.receiver_state, self.shipment_data['receiver_state'])
+
+        # Invalid sender state
+        invalid_data = self.shipment_data.copy()
+        invalid_data['sender_state'] = 'XX'
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_weight_validation(self):
+        """Test shipment weight validation"""
+        # Valid weight
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(shipment.weight, self.shipment_data['weight'])
+
+        # Invalid weight (negative)
+        invalid_data = self.shipment_data.copy()
+        invalid_data['weight'] = Decimal('-1.0')
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+    def test_shipment_tracking_number_format(self):
+        """Test shipment tracking number format"""
+        shipment = Shipment.objects.create(**self.shipment_data)
+
+        # Should end with -MY for Malaysia
+        self.assertTrue(shipment.tracking_number.endswith('-MY'))
+
+        # Should be unique
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**self.shipment_data)
+
+    def test_shipment_dimensions_validation(self):
+        """Test shipment dimensions validation"""
+        # Valid dimensions
+        shipment = Shipment.objects.create(**self.shipment_data)
+        self.assertEqual(shipment.length, self.shipment_data['length'])
+        self.assertEqual(shipment.width, self.shipment_data['width'])
+        self.assertEqual(shipment.height, self.shipment_data['height'])
+
+        # Invalid dimensions (negative)
+        invalid_data = self.shipment_data.copy()
+        invalid_data['length'] = Decimal('-1.0')
+        with self.assertRaises(Exception):
+            Shipment.objects.create(**invalid_data)
+
+
+class VehicleModelTest(TestCase):
+    """Test cases for Vehicle model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Logistics Sdn Bhd',
+            schema_name='test_logistics',
+            domain='testlogistics.com',
+            business_type='logistics'
+        )
+
+        self.user = User.objects.create_user(
+            username='manager',
+            email='manager@test.com',
+            password='test123',
+            tenant=self.tenant,
+            role='admin'
+        )
+
+        self.vehicle_data = {
+            'tenant': self.tenant,
+            'vehicle_number': 'V1234',
+            'registration_number': 'WAB1234',
+            'vehicle_type': 'van',
+            'make': 'Toyota',
+            'model': 'Hiace',
+            'year': 2020,
+            'color': 'White',
+            'chassis_number': 'MR0HE3CD5L123456',
+            'engine_number': '2TR123456',
+            'capacity': 1000,  # kg
+            'volume_capacity': 10.0,  # cubic meters
+            'fuel_type': 'petrol',
+            'fuel_capacity': 70,  # liters
+            'current_fuel': 50,  # liters
+            'purchase_date': date(2020, 1, 1),
+            'purchase_price': Decimal('120000.00'),
+            'insurance_policy': 'INS-2024-001234',
+            'insurance_expiry': date.today() + timedelta(days=365),
+            'road_tax_expiry': date.today() + timedelta(days=180),
+            'inspection_expiry': date.today() + timedelta(days=90),
+            'current_mileage': 50000,
+            'last_service_mileage': 45000,
+            'next_service_mileage': 55000,
+            'status': 'active',
+            'assigned_driver': None,
+            'gps_device_id': 'GPS001234',
+            'is_active': True,
+            'notes': 'Well-maintained vehicle',
+            'created_by': self.user
+        }
+
+    def test_create_vehicle(self):
+        """Test creating a new vehicle"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.tenant, self.tenant)
+        self.assertEqual(vehicle.vehicle_number, self.vehicle_data['vehicle_number'])
+        self.assertEqual(vehicle.registration_number, self.vehicle_data['registration_number'])
+        self.assertEqual(vehicle.vehicle_type, self.vehicle_data['vehicle_type'])
+        self.assertEqual(vehicle.make, self.vehicle_data['make'])
+        self.assertEqual(vehicle.model, self.vehicle_data['model'])
+        self.assertEqual(vehicle.year, self.vehicle_data['year'])
+        self.assertEqual(vehicle.capacity, self.vehicle_data['capacity'])
+        self.assertEqual(vehicle.status, self.vehicle_data['status'])
+        self.assertTrue(vehicle.is_active)
+
+    def test_vehicle_string_representation(self):
+        """Test vehicle string representation"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(str(vehicle), f"{vehicle.make} {vehicle.model} ({vehicle.registration_number})")
+
+    def test_vehicle_age(self):
+        """Test vehicle age calculation"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+
+        # Age should be calculated based on purchase date
+        today = date.today()
+        expected_age = today.year - vehicle.purchase_date.year
+        if today.month < vehicle.purchase_date.month or (today.month == vehicle.purchase_date.month and today.day < vehicle.purchase_date.day):
+            expected_age -= 1
+
+        self.assertEqual(vehicle.age, expected_age)
+
+    def test_vehicle_service_due(self):
+        """Test vehicle service due status"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+
+        # Service not due yet
+        self.assertFalse(vehicle.service_due)
+
+        # Mark as service due
+        vehicle.current_mileage = 56000
+        vehicle.save()
+
+        self.assertTrue(vehicle.service_due)
+
+    def test_vehicle_insurance_expiry_status(self):
+        """Test vehicle insurance expiry status"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+
+        # Insurance not expired
+        self.assertFalse(vehicle.insurance_expired)
+
+        # Mark as expired
+        vehicle.insurance_expiry = date.today() - timedelta(days=1)
+        vehicle.save()
+
+        self.assertTrue(vehicle.insurance_expired)
+
+    def test_vehicle_road_tax_expiry_status(self):
+        """Test vehicle road tax expiry status"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+
+        # Road tax not expired
+        self.assertFalse(vehicle.road_tax_expired)
+
+        # Mark as expired
+        vehicle.road_tax_expiry = date.today() - timedelta(days=1)
+        vehicle.save()
+
+        self.assertTrue(vehicle.road_tax_expired)
+
+    def test_vehicle_inspection_expiry_status(self):
+        """Test vehicle inspection expiry status"""
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+
+        # Inspection not expired
+        self.assertFalse(vehicle.inspection_expired)
+
+        # Mark as expired
+        vehicle.inspection_expiry = date.today() - timedelta(days=1)
+        vehicle.save()
+
+        self.assertTrue(vehicle.inspection_expired)
+
+    def test_vehicle_type_choices(self):
+        """Test vehicle type validation"""
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['vehicle_type'] = 'invalid_type'
+
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_fuel_type_choices(self):
+        """Test vehicle fuel type validation"""
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['fuel_type'] = 'invalid_fuel'
+
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_status_choices(self):
+        """Test vehicle status validation"""
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_malaysian_registration_validation(self):
+        """Test Malaysian vehicle registration validation"""
+        # Valid registration number
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.registration_number, self.vehicle_data['registration_number'])
+
+        # Invalid registration number format
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['registration_number'] = 'ABC123'
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_mileage_validation(self):
+        """Test vehicle mileage validation"""
+        # Valid mileage
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.current_mileage, self.vehicle_data['current_mileage'])
+
+        # Invalid mileage (negative)
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['current_mileage'] = -1000
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_capacity_validation(self):
+        """Test vehicle capacity validation"""
+        # Valid capacity
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.capacity, self.vehicle_data['capacity'])
+
+        # Invalid capacity (negative)
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['capacity'] = -100
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_year_validation(self):
+        """Test vehicle year validation"""
+        # Valid year
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.year, self.vehicle_data['year'])
+
+        # Invalid year (too old)
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['year'] = 1950
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+    def test_vehicle_fuel_level_validation(self):
+        """Test vehicle fuel level validation"""
+        # Valid fuel level
+        vehicle = Vehicle.objects.create(**self.vehicle_data)
+        self.assertEqual(vehicle.current_fuel, self.vehicle_data['current_fuel'])
+
+        # Invalid fuel level (negative)
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['current_fuel'] = -10
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)
+
+        # Invalid fuel level (exceeds capacity)
+        invalid_data = self.vehicle_data.copy()
+        invalid_data['current_fuel'] = 100
+        with self.assertRaises(Exception):
+            Vehicle.objects.create(**invalid_data)

backend/tests/unit/models/test_retail_models.py

@@ -0,0 +1,350 @@
+"""
+Unit tests for Retail Models
+
+Tests for retail module models:
+- Product
+- Sale
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.modules.retail.models.product import Product
+from backend.src.modules.retail.models.sale import Sale, SaleItem
+
+User = get_user_model()
+
+
+class ProductModelTest(TestCase):
+    """Test cases for Product model"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.user = User.objects.create_user(
+            username='testuser',
+            email='user@test.com',
+            password='test123',
+            tenant=self.tenant
+        )
+
+        self.product_data = {
+            'tenant': self.tenant,
+            'sku': 'PRD-001',
+            'name': 'Test Product',
+            'description': 'A test product for unit testing',
+            'category': 'electronics',
+            'brand': 'Test Brand',
+            'barcode': '1234567890123',
+            'unit': 'piece',
+            'current_stock': 100,
+            'minimum_stock': 10,
+            'maximum_stock': 500,
+            'reorder_point': 15,
+            'purchase_price': Decimal('50.00'),
+            'selling_price': Decimal('100.00'),
+            'wholesale_price': Decimal('80.00'),
+            'tax_rate': 10.0,
+            'is_taxable': True,
+            'is_active': True,
+            'requires_prescription': False,
+            'is_halal': True,
+            'msme_certified': True,
+            'created_by': self.user
+        }
+
+    def test_create_product(self):
+        """Test creating a new product"""
+        product = Product.objects.create(**self.product_data)
+        self.assertEqual(product.tenant, self.tenant)
+        self.assertEqual(product.sku, self.product_data['sku'])
+        self.assertEqual(product.name, self.product_data['name'])
+        self.assertEqual(product.current_stock, self.product_data['current_stock'])
+        self.assertEqual(product.purchase_price, self.product_data['purchase_price'])
+        self.assertEqual(product.selling_price, self.product_data['selling_price'])
+        self.assertTrue(product.is_active)
+        self.assertTrue(product.is_halal)
+
+    def test_product_string_representation(self):
+        """Test product string representation"""
+        product = Product.objects.create(**self.product_data)
+        self.assertEqual(str(product), f"{product.name} ({product.sku})")
+
+    def test_product_is_low_stock(self):
+        """Test product low stock detection"""
+        product = Product.objects.create(**self.product_data)
+
+        # Normal stock level
+        self.assertFalse(product.is_low_stock)
+
+        # Low stock level
+        product.current_stock = 5
+        product.save()
+        self.assertTrue(product.is_low_stock)
+
+    def test_product_profit_margin(self):
+        """Test product profit margin calculation"""
+        product = Product.objects.create(**self.product_data)
+
+        expected_margin = ((product.selling_price - product.purchase_price) / product.selling_price) * 100
+        self.assertAlmostEqual(product.profit_margin, expected_margin)
+
+    def test_product_category_choices(self):
+        """Test product category validation"""
+        invalid_data = self.product_data.copy()
+        invalid_data['category'] = 'invalid_category'
+
+        with self.assertRaises(Exception):
+            Product.objects.create(**invalid_data)
+
+    def test_product_unit_choices(self):
+        """Test product unit validation"""
+        invalid_data = self.product_data.copy()
+        invalid_data['unit'] = 'invalid_unit'
+
+        with self.assertRaises(Exception):
+            Product.objects.create(**invalid_data)
+
+    def test_product_barcode_validation(self):
+        """Test product barcode validation"""
+        # Valid barcode
+        product = Product.objects.create(**self.product_data)
+        self.assertEqual(product.barcode, self.product_data['barcode'])
+
+        # Invalid barcode (too long)
+        invalid_data = self.product_data.copy()
+        invalid_data['barcode'] = '1' * 14
+        with self.assertRaises(Exception):
+            Product.objects.create(**invalid_data)
+
+    def test_product_stock_validation(self):
+        """Test product stock validation"""
+        invalid_data = self.product_data.copy()
+        invalid_data['current_stock'] = -1
+
+        with self.assertRaises(Exception):
+            Product.objects.create(**invalid_data)
+
+        invalid_data['current_stock'] = 0
+        invalid_data['minimum_stock'] = -5
+
+        with self.assertRaises(Exception):
+            Product.objects.create(**invalid_data)
+
+
+class SaleModelTest(TestCase):
+    """Test cases for Sale and SaleItem models"""
+
+    def setUp(self):
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.user = User.objects.create_user(
+            username='testuser',
+            email='user@test.com',
+            password='test123',
+            tenant=self.tenant
+        )
+
+        self.product1 = Product.objects.create(
+            tenant=self.tenant,
+            sku='PRD-001',
+            name='Product 1',
+            category='electronics',
+            unit='piece',
+            current_stock=100,
+            minimum_stock=10,
+            purchase_price=Decimal('50.00'),
+            selling_price=Decimal('100.00'),
+            tax_rate=10.0,
+            created_by=self.user
+        )
+
+        self.product2 = Product.objects.create(
+            tenant=self.tenant,
+            sku='PRD-002',
+            name='Product 2',
+            category='electronics',
+            unit='piece',
+            current_stock=50,
+            minimum_stock=5,
+            purchase_price=Decimal('30.00'),
+            selling_price=Decimal('60.00'),
+            tax_rate=10.0,
+            created_by=self.user
+        )
+
+        self.sale_data = {
+            'tenant': self.tenant,
+            'invoice_number': 'INV-2024010001',
+            'customer_name': 'Test Customer',
+            'customer_email': 'customer@test.com',
+            'customer_phone': '+60123456789',
+            'customer_ic': '000101-01-0001',
+            'sale_date': timezone.now(),
+            'status': 'completed',
+            'payment_method': 'cash',
+            'payment_status': 'paid',
+            'sales_person': self.user,
+            'notes': 'Test sale for unit testing'
+        }
+
+    def test_create_sale(self):
+        """Test creating a new sale"""
+        sale = Sale.objects.create(**self.sale_data)
+        self.assertEqual(sale.tenant, self.tenant)
+        self.assertEqual(sale.invoice_number, self.sale_data['invoice_number'])
+        self.assertEqual(sale.customer_name, self.sale_data['customer_name'])
+        self.assertEqual(sale.status, self.sale_data['status'])
+        self.assertEqual(sale.payment_status, self.sale_data['payment_status'])
+        self.assertEqual(sale.sales_person, self.user)
+
+    def test_sale_string_representation(self):
+        """Test sale string representation"""
+        sale = Sale.objects.create(**self.sale_data)
+        self.assertEqual(str(sale), f"Invoice #{sale.invoice_number} - {sale.customer_name}")
+
+    def test_create_sale_item(self):
+        """Test creating a sale item"""
+        sale = Sale.objects.create(**self.sale_data)
+
+        sale_item_data = {
+            'sale': sale,
+            'product': self.product1,
+            'quantity': 2,
+            'unit_price': Decimal('100.00'),
+            'discount_percentage': 0.0,
+            'tax_rate': 10.0,
+            'notes': 'Test sale item'
+        }
+
+        sale_item = SaleItem.objects.create(**sale_item_data)
+        self.assertEqual(sale_item.sale, sale)
+        self.assertEqual(sale_item.product, self.product1)
+        self.assertEqual(sale_item.quantity, 2)
+        self.assertEqual(sale_item.unit_price, Decimal('100.00'))
+
+    def test_sale_item_subtotal(self):
+        """Test sale item subtotal calculation"""
+        sale = Sale.objects.create(**self.sale_data)
+
+        sale_item = SaleItem.objects.create(
+            sale=sale,
+            product=self.product1,
+            quantity=2,
+            unit_price=Decimal('100.00'),
+            tax_rate=10.0
+        )
+
+        expected_subtotal = Decimal('200.00')  # 2 * 100.00
+        self.assertEqual(sale_item.subtotal, expected_subtotal)
+
+    def test_sale_item_tax_amount(self):
+        """Test sale item tax amount calculation"""
+        sale = Sale.objects.create(**self.sale_data)
+
+        sale_item = SaleItem.objects.create(
+            sale=sale,
+            product=self.product1,
+            quantity=2,
+            unit_price=Decimal('100.00'),
+            tax_rate=10.0
+        )
+
+        expected_tax = Decimal('20.00')  # 200.00 * 0.10
+        self.assertEqual(sale_item.tax_amount, expected_tax)
+
+    def test_sale_item_total_amount(self):
+        """Test sale item total amount calculation"""
+        sale = Sale.objects.create(**self.sale_data)
+
+        sale_item = SaleItem.objects.create(
+            sale=sale,
+            product=self.product1,
+            quantity=2,
+            unit_price=Decimal('100.00'),
+            tax_rate=10.0
+        )
+
+        expected_total = Decimal('220.00')  # 200.00 + 20.00
+        self.assertEqual(sale_item.total_amount, expected_total)
+
+    def test_sale_calculate_totals(self):
+        """Test sale total calculations"""
+        sale = Sale.objects.create(**self.sale_data)
+
+        # Create multiple sale items
+        SaleItem.objects.create(
+            sale=sale,
+            product=self.product1,
+            quantity=2,
+            unit_price=Decimal('100.00'),
+            tax_rate=10.0
+        )
+
+        SaleItem.objects.create(
+            sale=sale,
+            product=self.product2,
+            quantity=1,
+            unit_price=Decimal('60.00'),
+            tax_rate=10.0
+        )
+
+        # Test the calculate_totals method
+        sale.calculate_totals()
+
+        expected_subtotal = Decimal('260.00')  # 200.00 + 60.00
+        expected_tax = Decimal('26.00')        # 20.00 + 6.00
+        expected_total = Decimal('286.00')      # 260.00 + 26.00
+
+        self.assertEqual(sale.subtotal_amount, expected_subtotal)
+        self.assertEqual(sale.tax_amount, expected_tax)
+        self.assertEqual(sale.total_amount, expected_total)
+
+    def test_sale_status_choices(self):
+        """Test sale status validation"""
+        invalid_data = self.sale_data.copy()
+        invalid_data['status'] = 'invalid_status'
+
+        with self.assertRaises(Exception):
+            Sale.objects.create(**invalid_data)
+
+    def test_sale_payment_method_choices(self):
+        """Test sale payment method validation"""
+        invalid_data = self.sale_data.copy()
+        invalid_data['payment_method'] = 'invalid_method'
+
+        with self.assertRaises(Exception):
+            Sale.objects.create(**invalid_data)
+
+    def test_malaysian_customer_validation(self):
+        """Test Malaysian customer validation"""
+        # Valid Malaysian IC
+        sale = Sale.objects.create(**self.sale_data)
+        self.assertEqual(sale.customer_ic, self.sale_data['customer_ic'])
+
+        # Valid Malaysian phone
+        self.assertEqual(sale.customer_phone, self.sale_data['customer_phone'])
+
+        # Invalid phone number
+        invalid_data = self.sale_data.copy()
+        invalid_data['customer_phone'] = '12345'
+        with self.assertRaises(Exception):
+            Sale.objects.create(**invalid_data)

backend/tests/unit/services/test_core_services.py

@@ -0,0 +1,638 @@
+"""
+Unit tests for Core Services
+
+Tests for all core services:
+- TenantService
+- UserService
+- SubscriptionService
+- ModuleService
+- PaymentService
+
+Author: Claude
+"""
+
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+from django.test import TestCase
+from django.contrib.auth import get_user_model
+from django.utils import timezone
+from decimal import Decimal
+from datetime import date, timedelta
+
+from backend.src.core.models.tenant import Tenant
+from backend.src.core.models.user import User
+from backend.src.core.models.subscription import Subscription
+from backend.src.core.models.module import Module
+from backend.src.core.models.payment import PaymentTransaction
+from backend.src.core.services.tenant_service import TenantService
+from backend.src.core.services.user_service import UserService
+from backend.src.core.services.subscription_service import SubscriptionService
+from backend.src.core.services.module_service import ModuleService
+from backend.src.core.services.payment_service import PaymentService
+
+User = get_user_model()
+
+
+class TenantServiceTest(TestCase):
+    """Test cases for TenantService"""
+
+    def setUp(self):
+        self.service = TenantService()
+        self.tenant_data = {
+            'name': 'Test Business Sdn Bhd',
+            'schema_name': 'test_business',
+            'domain': 'testbusiness.com',
+            'business_type': 'retail',
+            'registration_number': '202401000001',
+            'tax_id': 'MY123456789',
+            'contact_email': 'contact@testbusiness.com',
+            'contact_phone': '+60123456789',
+            'address': '123 Test Street',
+            'city': 'Kuala Lumpur',
+            'state': 'KUL',
+            'postal_code': '50000'
+        }
+
+    def test_create_tenant_success(self):
+        """Test successful tenant creation"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        self.assertEqual(tenant.name, self.tenant_data['name'])
+        self.assertEqual(tenant.schema_name, self.tenant_data['schema_name'])
+        self.assertTrue(tenant.is_active)
+        self.assertEqual(tenant.subscription_tier, 'free')
+
+    def test_create_tenant_invalid_data(self):
+        """Test tenant creation with invalid data"""
+        invalid_data = self.tenant_data.copy()
+        invalid_data['name'] = ''  # Empty name
+
+        with self.assertRaises(Exception):
+            self.service.create_tenant(invalid_data)
+
+    def test_get_tenant_by_id(self):
+        """Test getting tenant by ID"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        retrieved_tenant = self.service.get_tenant_by_id(tenant.id)
+        self.assertEqual(retrieved_tenant, tenant)
+
+    def test_get_tenant_by_schema_name(self):
+        """Test getting tenant by schema name"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        retrieved_tenant = self.service.get_tenant_by_schema_name(tenant.schema_name)
+        self.assertEqual(retrieved_tenant, tenant)
+
+    def test_update_tenant(self):
+        """Test updating tenant information"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        update_data = {'name': 'Updated Business Name'}
+        updated_tenant = self.service.update_tenant(tenant.id, update_data)
+        self.assertEqual(updated_tenant.name, 'Updated Business Name')
+
+    def test_activate_tenant(self):
+        """Test tenant activation"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        tenant.is_active = False
+        tenant.save()
+
+        activated_tenant = self.service.activate_tenant(tenant.id)
+        self.assertTrue(activated_tenant.is_active)
+
+    def test_deactivate_tenant(self):
+        """Test tenant deactivation"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        deactivated_tenant = self.service.deactivate_tenant(tenant.id)
+        self.assertFalse(deactivated_tenant.is_active)
+
+    def test_get_tenant_statistics(self):
+        """Test getting tenant statistics"""
+        tenant = self.service.create_tenant(self.tenant_data)
+        stats = self.service.get_tenant_statistics(tenant.id)
+
+        self.assertIn('total_users', stats)
+        self.assertIn('active_subscriptions', stats)
+        self.assertIn('total_modules', stats)
+
+
+class UserServiceTest(TestCase):
+    """Test cases for UserService"""
+
+    def setUp(self):
+        self.service = UserService()
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+    def test_create_user_success(self):
+        """Test successful user creation"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'first_name': 'Test',
+            'last_name': 'User',
+            'phone': '+60123456789',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        user = self.service.create_user(user_data)
+        self.assertEqual(user.username, user_data['username'])
+        self.assertEqual(user.email, user_data['email'])
+        self.assertEqual(user.tenant, self.tenant)
+        self.assertTrue(user.check_password('test123'))
+
+    def test_create_superuser(self):
+        """Test superuser creation"""
+        user_data = {
+            'username': 'admin',
+            'email': 'admin@test.com',
+            'password': 'admin123',
+            'first_name': 'Admin',
+            'last_name': 'User'
+        }
+
+        user = self.service.create_superuser(user_data)
+        self.assertTrue(user.is_staff)
+        self.assertTrue(user.is_superuser)
+        self.assertEqual(user.role, 'admin')
+
+    def test_authenticate_user_success(self):
+        """Test successful user authentication"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        self.service.create_user(user_data)
+        authenticated_user = self.service.authenticate_user(
+            user_data['username'],
+            user_data['password']
+        )
+
+        self.assertIsNotNone(authenticated_user)
+        self.assertEqual(authenticated_user.username, user_data['username'])
+
+    def test_authenticate_user_failure(self):
+        """Test failed user authentication"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        self.service.create_user(user_data)
+        authenticated_user = self.service.authenticate_user(
+            user_data['username'],
+            'wrongpassword'
+        )
+
+        self.assertIsNone(authenticated_user)
+
+    def test_update_user_profile(self):
+        """Test updating user profile"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        user = self.service.create_user(user_data)
+        update_data = {'first_name': 'Updated', 'last_name': 'Name'}
+        updated_user = self.service.update_user(user.id, update_data)
+
+        self.assertEqual(updated_user.first_name, 'Updated')
+        self.assertEqual(updated_user.last_name, 'Name')
+
+    def test_change_password(self):
+        """Test changing user password"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        user = self.service.create_user(user_data)
+        success = self.service.change_password(user.id, 'newpassword123')
+
+        self.assertTrue(success)
+        self.assertTrue(user.check_password('newpassword123'))
+
+    def test_deactivate_user(self):
+        """Test user deactivation"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        user = self.service.create_user(user_data)
+        deactivated_user = self.service.deactivate_user(user.id)
+
+        self.assertFalse(deactivated_user.is_active)
+
+    def test_get_users_by_tenant(self):
+        """Test getting users by tenant"""
+        user_data = {
+            'username': 'testuser',
+            'email': 'user@test.com',
+            'password': 'test123',
+            'tenant': self.tenant,
+            'role': 'staff'
+        }
+
+        self.service.create_user(user_data)
+        users = self.service.get_users_by_tenant(self.tenant.id)
+
+        self.assertEqual(len(users), 1)
+        self.assertEqual(users[0].username, user_data['username'])
+
+
+class SubscriptionServiceTest(TestCase):
+    """Test cases for SubscriptionService"""
+
+    def setUp(self):
+        self.service = SubscriptionService()
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+    def test_create_subscription_success(self):
+        """Test successful subscription creation"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30)
+        }
+
+        subscription = self.service.create_subscription(subscription_data)
+        self.assertEqual(subscription.tenant, self.tenant)
+        self.assertEqual(subscription.plan, 'premium')
+        self.assertEqual(subscription.status, 'active')
+
+    def test_upgrade_subscription(self):
+        """Test subscription upgrade"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'basic',
+            'amount': Decimal('99.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30)
+        }
+
+        subscription = self.service.create_subscription(subscription_data)
+        upgraded_subscription = self.service.upgrade_subscription(
+            subscription.id,
+            'premium',
+            Decimal('299.00')
+        )
+
+        self.assertEqual(upgraded_subscription.plan, 'premium')
+        self.assertEqual(upgraded_subscription.amount, Decimal('299.00'))
+
+    def test_cancel_subscription(self):
+        """Test subscription cancellation"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30)
+        }
+
+        subscription = self.service.create_subscription(subscription_data)
+        cancelled_subscription = self.service.cancel_subscription(subscription.id)
+
+        self.assertEqual(cancelled_subscription.status, 'cancelled')
+
+    def test_renew_subscription(self):
+        """Test subscription renewal"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today() - timedelta(days=29),
+            'end_date': date.today() + timedelta(days=1)
+        }
+
+        subscription = self.service.create_subscription(subscription_data)
+        renewed_subscription = self.service.renew_subscription(subscription.id)
+
+        self.assertEqual(renewed_subscription.status, 'active')
+        self.assertGreater(renewed_subscription.end_date, subscription.end_date)
+
+    def test_check_subscription_status(self):
+        """Test subscription status check"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30)
+        }
+
+        subscription = self.service.create_subscription(subscription_data)
+        status = self.service.check_subscription_status(self.tenant.id)
+
+        self.assertTrue(status['is_active'])
+        self.assertEqual(status['plan'], 'premium')
+
+    def test_get_subscription_history(self):
+        """Test getting subscription history"""
+        subscription_data = {
+            'tenant': self.tenant,
+            'plan': 'premium',
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'billing_cycle': 'monthly',
+            'start_date': date.today(),
+            'end_date': date.today() + timedelta(days=30)
+        }
+
+        self.service.create_subscription(subscription_data)
+        history = self.service.get_subscription_history(self.tenant.id)
+
+        self.assertEqual(len(history), 1)
+        self.assertEqual(history[0]['plan'], 'premium')
+
+
+class ModuleServiceTest(TestCase):
+    """Test cases for ModuleService"""
+
+    def setUp(self):
+        self.service = ModuleService()
+
+    def test_create_module_success(self):
+        """Test successful module creation"""
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        module = self.service.create_module(module_data)
+        self.assertEqual(module.name, module_data['name'])
+        self.assertEqual(module.code, module_data['code'])
+        self.assertTrue(module.is_active)
+
+    def test_get_module_by_code(self):
+        """Test getting module by code"""
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        module = self.service.create_module(module_data)
+        retrieved_module = self.service.get_module_by_code('test')
+
+        self.assertEqual(retrieved_module, module)
+
+    def test_get_modules_by_category(self):
+        """Test getting modules by category"""
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        self.service.create_module(module_data)
+        modules = self.service.get_modules_by_category('industry')
+
+        self.assertEqual(len(modules), 1)
+        self.assertEqual(modules[0].code, 'test')
+
+    def test_activate_module(self):
+        """Test module activation"""
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': False,
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        module = self.service.create_module(module_data)
+        activated_module = self.service.activate_module(module.id)
+
+        self.assertTrue(activated_module.is_active)
+
+    def test_deactivate_module(self):
+        """Test module deactivation"""
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        module = self.service.create_module(module_data)
+        deactivated_module = self.service.deactivate_module(module.id)
+
+        self.assertFalse(deactivated_module.is_active)
+
+    def test_check_module_dependencies(self):
+        """Test module dependency checking"""
+        # Create dependent module first
+        dependent_module_data = {
+            'name': 'Core Module',
+            'code': 'core',
+            'description': 'Core module',
+            'category': 'core',
+            'version': '1.0.0',
+            'is_active': True,
+            'config_schema': {'features': ['core']},
+            'pricing_tier': 'free'
+        }
+
+        self.service.create_module(dependent_module_data)
+
+        # Create module with dependency
+        module_data = {
+            'name': 'Test Module',
+            'code': 'test',
+            'description': 'A test module',
+            'category': 'industry',
+            'version': '1.0.0',
+            'is_active': True,
+            'dependencies': ['core'],
+            'config_schema': {'features': ['test']},
+            'pricing_tier': 'premium'
+        }
+
+        module = self.service.create_module(module_data)
+        dependencies = self.service.check_module_dependencies(module.id)
+
+        self.assertTrue(dependencies['dependencies_met'])
+        self.assertEqual(len(dependencies['dependencies']), 1)
+
+
+class PaymentServiceTest(TestCase):
+    """Test cases for PaymentService"""
+
+    def setUp(self):
+        self.service = PaymentService()
+        self.tenant = Tenant.objects.create(
+            name='Test Business Sdn Bhd',
+            schema_name='test_business',
+            domain='testbusiness.com',
+            business_type='retail'
+        )
+
+        self.subscription = Subscription.objects.create(
+            tenant=self.tenant,
+            plan='premium',
+            status='active',
+            start_date=date.today(),
+            end_date=date.today() + timedelta(days=30),
+            amount=Decimal('299.00'),
+            currency='MYR'
+        )
+
+    @patch('backend.src.core.services.payment_service.PaymentService.process_payment_gateway')
+    def test_create_payment_success(self, mock_process_payment):
+        """Test successful payment creation"""
+        mock_process_payment.return_value = {'success': True, 'transaction_id': 'TX123456'}
+
+        payment_data = {
+            'tenant': self.tenant,
+            'subscription': self.subscription,
+            'amount': Decimal('299.00'),
+            'currency': 'MYR',
+            'payment_method': 'fpx',
+            'description': 'Monthly subscription payment'
+        }
+
+        payment = self.service.create_payment(payment_data)
+        self.assertEqual(payment.tenant, self.tenant)
+        self.assertEqual(payment.amount, Decimal('299.00'))
+        self.assertEqual(payment.status, 'completed')
+
+    def test_create_payment_invalid_amount(self):
+        """Test payment creation with invalid amount"""
+        payment_data = {
+            'tenant': self.tenant,
+            'subscription': self.subscription,
+            'amount': Decimal('-100.00'),
+            'currency': 'MYR',
+            'payment_method': 'fpx',
+            'description': 'Invalid payment'
+        }
+
+        with self.assertRaises(Exception):
+            self.service.create_payment(payment_data)
+
+    @patch('backend.src.core.services.payment_service.PaymentService.process_payment_gateway')
+    def test_process_payment_refund(self, mock_process_payment):
+        """Test payment refund processing"""
+        mock_process_payment.return_value = {'success': True, 'refund_id': 'RF123456'}
+
+        payment = PaymentTransaction.objects.create(
+            tenant=self.tenant,
+            subscription=self.subscription,
+            transaction_id='TX123456',
+            amount=Decimal('299.00'),
+            currency='MYR',
+            payment_method='fpx',
+            status='completed',
+            payment_date=timezone.now()
+        )
+
+        refund_result = self.service.process_refund(payment.id, Decimal('100.00'))
+        self.assertTrue(refund_result['success'])
+        self.assertEqual(refund_result['refund_id'], 'RF123456')
+
+    def test_get_payment_history(self):
+        """Test getting payment history"""
+        payment = PaymentTransaction.objects.create(
+            tenant=self.tenant,
+            subscription=self.subscription,
+            transaction_id='TX123456',
+            amount=Decimal('299.00'),
+            currency='MYR',
+            payment_method='fpx',
+            status='completed',
+            payment_date=timezone.now()
+        )
+
+        history = self.service.get_payment_history(self.tenant.id)
+        self.assertEqual(len(history), 1)
+        self.assertEqual(history[0]['transaction_id'], 'TX123456')
+
+    def test_check_payment_status(self):
+        """Test checking payment status"""
+        payment = PaymentTransaction.objects.create(
+            tenant=self.tenant,
+            subscription=self.subscription,
+            transaction_id='TX123456',
+            amount=Decimal('299.00'),
+            currency='MYR',
+            payment_method='fpx',
+            status='completed',
+            payment_date=timezone.now()
+        )
+
+        status = self.service.check_payment_status(payment.transaction_id)
+        self.assertEqual(status['status'], 'completed')
+        self.assertEqual(status['amount'], Decimal('299.00'))
+
+    def test_validate_payment_method(self):
+        """Test payment method validation"""
+        valid_methods = ['fpx', 'credit_card', 'debit_card', 'ewallet', 'cash']
+        for method in valid_methods:
+            is_valid = self.service.validate_payment_method(method)
+            self.assertTrue(is_valid)
+
+        invalid_method = 'invalid_method'
+        is_valid = self.service.validate_payment_method(invalid_method)
+        self.assertFalse(is_valid)

backend/tests/unit/test_caching.py

@@ -0,0 +1,686 @@
+"""
+Unit tests for caching strategies and managers.
+"""
+
+import json
+import time
+from datetime import datetime, timedelta
+from unittest.mock import Mock, patch, MagicMock
+from django.test import TestCase, override_settings
+from django.core.cache import cache
+from django.conf import settings
+from django.contrib.auth import get_user_model
+from django.db import connection
+from django.http import HttpRequest, HttpResponse
+from django.test import RequestFactory
+from rest_framework.test import APITestCase
+
+from core.caching.cache_manager import (
+    CacheManager, CacheKeyGenerator, MalaysianDataCache,
+    QueryCache, TenantCacheManager, CacheWarmer
+)
+from core.caching.strategies import (
+    WriteThroughCache, WriteBehindCache, ReadThroughCache,
+    RefreshAheadCache, CacheAsidePattern, MultiLevelCache,
+    MalaysianCacheStrategies, CacheEvictionPolicy,
+    cache_view_response, cache_query_results
+)
+from core.caching.django_integration import (
+    TenantCacheMiddleware, CacheMiddleware, DatabaseCacheMiddleware,
+    MalaysianCacheMiddleware, get_cache_config
+)
+from core.caching.config import CacheConfig
+
+User = get_user_model()
+
+
+class CacheKeyGeneratorTest(TestCase):
+    """Test cache key generation."""
+
+    def setUp(self):
+        self.generator = CacheKeyGenerator()
+
+    def test_generate_basic_key(self):
+        """Test basic key generation."""
+        key = self.generator.generate_key("test", "123")
+        self.assertIn("my_sme", key)
+        self.assertIn("test", key)
+        self.assertIn("123", key)
+
+    def test_generate_key_with_context(self):
+        """Test key generation with context."""
+        context = {"filter": "active", "sort": "name"}
+        key = self.generator.generate_key("test", "123", context=context)
+        self.assertIn("my_sme", key)
+        self.assertIn("test", key)
+        self.assertIn("123", key)
+
+    def test_generate_malaysian_key(self):
+        """Test Malaysian-specific key generation."""
+        key = self.generator.generate_malaysian_key("ic", "1234567890")
+        self.assertIn("my_sme", key)
+        self.assertIn("ic_1234567890", key)
+        self.assertIn("my", key)
+
+    def test_tenant_prefix_inclusion(self):
+        """Test tenant prefix inclusion in keys."""
+        key = self.generator.generate_key("test", "123")
+        self.assertIn("tenant_", key)
+
+
+class CacheManagerTest(TestCase):
+    """Test cache manager operations."""
+
+    def setUp(self):
+        self.manager = CacheManager()
+
+    def test_set_and_get(self):
+        """Test basic set and get operations."""
+        key = "test_key"
+        value = {"data": "test_value"}
+
+        result = self.manager.set(key, value)
+        self.assertTrue(result)
+
+        retrieved = self.manager.get(key)
+        self.assertEqual(retrieved, value)
+
+    def test_get_default_value(self):
+        """Test get with default value."""
+        key = "nonexistent_key"
+        default = {"default": "value"}
+
+        result = self.manager.get(key, default)
+        self.assertEqual(result, default)
+
+    def test_delete_key(self):
+        """Test key deletion."""
+        key = "test_key"
+        value = "test_value"
+
+        self.manager.set(key, value)
+        result = self.manager.delete(key)
+        self.assertTrue(result)
+
+        retrieved = self.manager.get(key)
+        self.assertIsNone(retrieved)
+
+    def test_clear_tenant_cache(self):
+        """Test tenant cache clearing."""
+        result = self.manager.clear_tenant_cache()
+        self.assertTrue(result)
+
+    def test_get_cache_stats(self):
+        """Test cache statistics."""
+        stats = self.manager.get_cache_stats()
+        self.assertIn("tenant", stats)
+        self.assertIn("redis_available", stats)
+        self.assertIn("default_timeout", stats)
+
+    @patch('core.caching.cache_manager.get_redis_connection')
+    def test_redis_connection_failure(self, mock_get_redis):
+        """Test graceful handling of Redis connection failure."""
+        mock_get_redis.side_effect = Exception("Connection failed")
+
+        manager = CacheManager()
+        self.assertIsNone(manager.redis_client)
+
+        stats = manager.get_cache_stats()
+        self.assertFalse(stats["redis_available"])
+
+
+class MalaysianDataCacheTest(TestCase):
+    """Test Malaysian data caching."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.malaysian_cache = MalaysianDataCache(self.cache_manager)
+
+    def test_ic_validation_caching(self):
+        """Test IC validation caching."""
+        ic_number = "1234567890"
+        validation_result = {"valid": True, "age": 30}
+
+        result = self.malaysian_cache.set_cached_ic_validation(ic_number, validation_result)
+        self.assertTrue(result)
+
+        retrieved = self.malaysian_cache.get_cached_ic_validation(ic_number)
+        self.assertEqual(retrieved, validation_result)
+
+    def test_sst_rate_caching(self):
+        """Test SST rate caching."""
+        state = "Johor"
+        category = "standard"
+        rate = 0.06
+
+        result = self.malaysian_cache.set_cached_sst_rate(state, category, rate)
+        self.assertTrue(result)
+
+        retrieved = self.malaysian_cache.get_cached_sst_rate(state, category)
+        self.assertEqual(retrieved, rate)
+
+    def test_postcode_data_caching(self):
+        """Test postcode data caching."""
+        postcode = "50000"
+        postcode_data = {"city": "Kuala Lumpur", "state": "WP Kuala Lumpur"}
+
+        result = self.malaysian_cache.set_cached_postcode_data(postcode, postcode_data)
+        self.assertTrue(result)
+
+        retrieved = self.malaysian_cache.get_cached_postcode_data(postcode)
+        self.assertEqual(retrieved, postcode_data)
+
+
+class QueryCacheTest(TestCase):
+    """Test query caching."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.query_cache = QueryCache(self.cache_manager)
+
+    def test_query_hash_generation(self):
+        """Test query hash generation."""
+        query = "SELECT * FROM users WHERE id = %s"
+        params = (1,)
+
+        hash1 = self.query_cache.generate_query_hash(query, params)
+        hash2 = self.query_cache.generate_query_hash(query, params)
+        self.assertEqual(hash1, hash2)
+
+        # Different params should produce different hash
+        hash3 = self.query_cache.generate_query_hash(query, (2,))
+        self.assertNotEqual(hash1, hash3)
+
+    def test_query_result_caching(self):
+        """Test query result caching."""
+        query = "SELECT * FROM test_table"
+        result = [{"id": 1, "name": "test"}]
+
+        success = self.query_cache.cache_query_result(query, result)
+        self.assertTrue(success)
+
+        retrieved = self.query_cache.get_cached_query_result(query)
+        self.assertEqual(retrieved, result)
+
+    def test_model_cache_invalidation(self):
+        """Test model cache invalidation."""
+        # Add some query hashes
+        self.query_cache.query_hashes.add("user_query_123")
+        self.query_cache.query_hashes.add("product_query_456")
+
+        invalidated = self.query_cache.invalidate_model_cache("user")
+        self.assertEqual(invalidated, 1)
+        self.assertIn("product_query_456", self.query_cache.query_hashes)
+        self.assertNotIn("user_query_123", self.query_cache.query_hashes)
+
+
+class TenantCacheManagerTest(TestCase):
+    """Test tenant cache management."""
+
+    def setUp(self):
+        self.tenant_manager = TenantCacheManager()
+
+    def test_get_cache_manager(self):
+        """Test getting cache manager for tenant."""
+        manager = self.tenant_manager.get_cache_manager(1)
+        self.assertIsInstance(manager, CacheManager)
+        self.assertEqual(manager.config.tenant_prefix, "tenant_1")
+
+    def test_cache_manager_reuse(self):
+        """Test cache manager reuse for same tenant."""
+        manager1 = self.tenant_manager.get_cache_manager(1)
+        manager2 = self.tenant_manager.get_cache_manager(1)
+        self.assertIs(manager1, manager2)
+
+    def test_get_tenant_cache_stats(self):
+        """Test tenant cache statistics."""
+        self.tenant_manager.get_cache_manager(1)
+        stats = self.tenant_manager.get_tenant_cache_stats()
+
+        self.assertIn("tenants", stats)
+        self.assertIn("total_tenants", stats)
+        self.assertEqual(stats["total_tenants"], 1)
+
+
+class CacheWarmerTest(TestCase):
+    """Test cache warming."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.warmer = CacheWarmer(self.cache_manager)
+
+    def test_warm_malaysian_data(self):
+        """Test warming Malaysian data."""
+        result = self.warmer.warm_malaysian_data()
+
+        self.assertIn("sst_rates", result)
+        self.assertIn("postcodes", result)
+        self.assertGreater(result["sst_rates"], 0)
+        self.assertGreater(result["postcodes"], 0)
+
+    def test_warm_user_data(self):
+        """Test warming user data."""
+        user = User.objects.create_user(
+            username="testuser",
+            email="test@example.com",
+            password="testpass123"
+        )
+
+        warmed = self.warmer.warm_user_data([user.id])
+        self.assertEqual(warmed, 1)
+
+        # Verify user data is cached
+        key = self.cache_manager.key_generator.generate_key("user", str(user.id))
+        cached_data = self.cache_manager.get(key)
+        self.assertIsNotNone(cached_data)
+        self.assertEqual(cached_data["id"], user.id)
+
+
+class WriteThroughCacheTest(TestCase):
+    """Test write-through caching."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.write_through = WriteThroughCache(self.cache_manager)
+
+    def test_write_through_operation(self):
+        """Test write-through operation."""
+        key = "test_key"
+        value = "test_value"
+
+        def db_operation():
+            return value
+
+        result = self.write_through.write_through(key, value, db_operation)
+        self.assertEqual(result, value)
+
+        # Verify cache is populated
+        cached_value = self.cache_manager.get(key)
+        self.assertEqual(cached_value, value)
+
+
+class ReadThroughCacheTest(TestCase):
+    """Test read-through caching."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.read_through = ReadThroughCache(self.cache_manager)
+
+    def test_read_through_operation(self):
+        """Test read-through operation."""
+        key = "test_key"
+        value = "test_value"
+
+        def db_operation():
+            return value
+
+        # First read - should hit database and cache
+        result1 = self.read_through.read_through(key, db_operation)
+        self.assertEqual(result1, value)
+
+        # Second read - should hit cache
+        result2 = self.read_through.read_through(key, db_operation)
+        self.assertEqual(result2, value)
+
+        # Verify cache was populated
+        cached_value = self.cache_manager.get(key)
+        self.assertEqual(cached_value, value)
+
+
+class CacheAsidePatternTest(TestCase):
+    """Test cache-aside pattern."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.cache_aside = CacheAsidePattern(self.cache_manager)
+
+    def test_get_or_set_operation(self):
+        """Test get-or-set operation."""
+        key = "test_key"
+        value = "test_value"
+
+        def db_operation():
+            return value
+
+        # First call - should set cache
+        result1 = self.cache_aside.get_or_set(key, db_operation)
+        self.assertEqual(result1, value)
+
+        # Second call - should get from cache
+        result2 = self.cache_aside.get_or_set(key, db_operation)
+        self.assertEqual(result2, value)
+
+    def test_invalidate_operation(self):
+        """Test cache invalidation."""
+        key = "test_key"
+        value = "test_value"
+
+        def db_operation():
+            return value
+
+        # Set cache
+        self.cache_aside.get_or_set(key, db_operation)
+
+        # Invalidate
+        result = self.cache_aside.invalidate(key)
+        self.assertTrue(result)
+
+        # Verify cache is cleared
+        cached_value = self.cache_manager.get(key)
+        self.assertIsNone(cached_value)
+
+
+class MultiLevelCacheTest(TestCase):
+    """Test multi-level caching."""
+
+    def setUp(self):
+        self.l1_cache = CacheManager()
+        self.l2_cache = CacheManager()
+        self.multi_cache = MultiLevelCache(self.l1_cache, self.l2_cache)
+
+    def test_multi_level_get_set(self):
+        """Test multi-level get and set operations."""
+        key = "test_key"
+        value = "test_value"
+
+        # Set value
+        result = self.multi_cache.set(key, value)
+        self.assertTrue(result)
+
+        # Get from multi-level cache
+        retrieved = self.multi_cache.get(key)
+        self.assertEqual(retrieved, value)
+
+    def test_l1_promotion(self):
+        """Test L1 cache promotion."""
+        key = "test_key"
+        value = "test_value"
+
+        # Set only in L2 cache
+        self.l2_cache.set(key, value)
+
+        # Get from multi-level cache - should promote to L1
+        retrieved = self.multi_cache.get(key)
+        self.assertEqual(retrieved, value)
+
+        # Verify it's now in L1 cache
+        l1_value = self.l1_cache.get(key)
+        self.assertEqual(l1_value, value)
+
+    def test_cache_statistics(self):
+        """Test cache statistics."""
+        key = "test_key"
+        value = "test_value"
+
+        # Initial stats
+        stats = self.multi_cache.get_stats()
+        self.assertEqual(stats["l1_hits"], 0)
+        self.assertEqual(stats["l2_hits"], 0)
+        self.assertEqual(stats["misses"], 0)
+
+        # Set and get
+        self.multi_cache.set(key, value)
+        self.multi_cache.get(key)  # L1 hit
+
+        stats = self.multi_cache.get_stats()
+        self.assertEqual(stats["l1_hits"], 1)
+        self.assertEqual(stats["misses"], 0)
+
+
+class MalaysianCacheStrategiesTest(TestCase):
+    """Test Malaysian cache strategies."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.malaysian_strategies = MalaysianCacheStrategies(self.cache_manager)
+
+    def test_ic_validation_caching(self):
+        """Test IC validation caching."""
+        ic_number = "1234567890"
+
+        def validation_func(ic):
+            return {"valid": True, "age": 30}
+
+        result = self.malaysian_strategies.cache_ic_validation(ic_number, validation_func)
+        self.assertEqual(result["valid"], True)
+
+        # Verify cached
+        cached = self.cache_manager.get(f"*:my:ic_validation_{ic_number}")
+        self.assertIsNotNone(cached)
+
+    def test_sst_calculation_caching(self):
+        """Test SST calculation caching."""
+        calculation_key = "johor_standard"
+
+        def calculation_func():
+            return 0.06
+
+        result = self.malaysian_strategies.cache_sst_calculation(calculation_key, calculation_func)
+        self.assertEqual(result, 0.06)
+
+    def test_postcode_lookup_caching(self):
+        """Test postcode lookup caching."""
+        postcode = "50000"
+
+        def lookup_func(pc):
+            return {"city": "Kuala Lumpur", "state": "WP Kuala Lumpur"}
+
+        result = self.malaysian_strategies.cache_postcode_lookup(postcode, lookup_func)
+        self.assertEqual(result["city"], "Kuala Lumpur")
+
+
+class CacheEvictionPolicyTest(TestCase):
+    """Test cache eviction policies."""
+
+    def setUp(self):
+        self.cache_manager = CacheManager()
+        self.eviction_policy = CacheEvictionPolicy(self.cache_manager)
+
+    def test_lru_eviction(self):
+        """Test LRU eviction."""
+        keys = ["key1", "key2", "key3"]
+
+        # Record access with different times
+        self.eviction_policy.record_access("key1")
+        time.sleep(0.1)
+        self.eviction_policy.record_access("key2")
+        time.sleep(0.1)
+        self.eviction_policy.record_access("key3")
+
+        # LRU should evict key1 (oldest access)
+        evicted = self.eviction_policy.lru_eviction(keys, 1)
+        self.assertEqual(evicted, ["key1"])
+
+    def test_lfu_eviction(self):
+        """Test LFU eviction."""
+        keys = ["key1", "key2", "key3"]
+
+        # Record different access frequencies
+        self.eviction_policy.record_access("key1")
+        self.eviction_policy.record_access("key2")
+        self.eviction_policy.record_access("key2")  # Access twice
+        self.eviction_policy.record_access("key3")
+        self.eviction_policy.record_access("key3")
+        self.eviction_policy.record_access("key3")  # Access three times
+
+        # LFU should evict key1 (least frequent)
+        evicted = self.eviction_policy.lfu_eviction(keys, 1)
+        self.assertEqual(evicted, ["key1"])
+
+    def test_fifo_eviction(self):
+        """Test FIFO eviction."""
+        keys = ["key1", "key2", "key3"]
+        evicted = self.eviction_policy.fifo_eviction(keys, 1)
+        self.assertEqual(evicted, ["key1"])
+
+
+class CacheMiddlewareTest(TestCase):
+    """Test cache middleware."""
+
+    def setUp(self):
+        self.factory = RequestFactory()
+        self.middleware = CacheMiddleware(self.get_response)
+
+    def get_response(self, request):
+        return HttpResponse("test response")
+
+    def test_middleware_process_request_cacheable(self):
+        """Test middleware process request for cacheable path."""
+        request = self.factory.get('/api/products/')
+        request.user = Mock()
+        request.user.is_authenticated = False
+
+        response = self.middleware.process_request(request)
+        self.assertIsNone(response)  # Should not return cached response
+
+    def test_middleware_process_request_non_cacheable(self):
+        """Test middleware process request for non-cacheable path."""
+        request = self.factory.get('/api/auth/login/')
+        request.user = Mock()
+        request.user.is_authenticated = False
+
+        response = self.middleware.process_request(request)
+        self.assertIsNone(response)  # Should bypass cache
+
+    def test_middleware_should_bypass_cache(self):
+        """Test cache bypass logic."""
+        request = self.factory.get('/api/products/')
+        request.user = Mock()
+        request.user.is_authenticated = True
+
+        should_bypass = self.middleware._should_bypass_cache(request)
+        self.assertTrue(should_bypass)  # Should bypass for authenticated users
+
+    def test_cache_key_generation(self):
+        """Test cache key generation."""
+        request = self.factory.get('/api/products/', {'category': 'electronics'})
+        request.user = Mock()
+        request.user.is_authenticated = False
+        request.tenant = Mock()
+        request.tenant.id = 1
+
+        key = self.middleware._generate_cache_key(request)
+        self.assertIn('/api/products/', key)
+        self.assertIn('tenant_1', key)
+
+
+class CacheConfigurationTest(TestCase):
+    """Test cache configuration."""
+
+    def test_cache_config_initialization(self):
+        """Test cache configuration initialization."""
+        config = CacheConfig()
+
+        self.assertIsInstance(config.default_timeout, int)
+        self.assertIsInstance(config.use_redis, bool)
+        self.assertIsInstance(config.tenant_isolation, bool)
+
+    def test_get_cache_config(self):
+        """Test getting cache configuration."""
+        config = get_cache_config()
+
+        self.assertIn('CACHES', config)
+        self.assertIn('CACHE_MIDDLEWARE_ALIAS', config)
+        self.assertIn('CACHE_MIDDLEWARE_SECONDS', config)
+
+
+class CacheManagementCommandTest(TestCase):
+    """Test cache management command."""
+
+    @patch('core.management.commands.cache_management.Command._output_results')
+    def test_command_initialization(self, mock_output):
+        """Test command initialization."""
+        from core.management.commands.cache_management import Command
+
+        command = Command()
+        self.assertIsNotNone(command.cache_manager)
+        self.assertIsNotNone(command.malaysian_cache)
+        self.assertIsNotNone(command.query_cache)
+
+    @patch('core.management.commands.cache_management.Command._output_results')
+    def test_stats_action(self, mock_output):
+        """Test stats action."""
+        from core.management.commands.cache_management import Command
+
+        command = Command()
+        command.action = 'stats'
+        command.cache_type = 'all'
+        command.output_format = 'table'
+
+        command.handle_stats()
+
+        # Verify _output_results was called
+        mock_output.assert_called_once()
+
+    @patch('core.management.commands.cache_management.Command._output_results')
+    def test_health_check_action(self, mock_output):
+        """Test health check action."""
+        from core.management.commands.cache_management import Command
+
+        command = Command()
+        command.action = 'health-check'
+        command.output_format = 'table'
+
+        command.handle_health_check()
+
+        # Verify _output_results was called
+        mock_output.assert_called_once()
+
+
+class CacheIntegrationTest(TestCase):
+    """Integration tests for caching system."""
+
+    def test_full_cache_workflow(self):
+        """Test complete cache workflow."""
+        # Create cache manager
+        cache_manager = CacheManager()
+
+        # Test Malaysian data caching
+        malaysian_cache = MalaysianDataCache(cache_manager)
+
+        # Cache IC validation
+        ic_result = {"valid": True, "age": 25}
+        malaysian_cache.set_cached_ic_validation("1234567890", ic_result)
+
+        # Retrieve cached result
+        cached_result = malaysian_cache.get_cached_ic_validation("1234567890")
+        self.assertEqual(cached_result, ic_result)
+
+        # Test query caching
+        query_cache = QueryCache(cache_manager)
+        query = "SELECT * FROM users WHERE id = %s"
+        result = [{"id": 1, "name": "test"}]
+
+        query_cache.cache_query_result(query, result)
+        cached_query_result = query_cache.get_cached_query_result(query)
+        self.assertEqual(cached_query_result, result)
+
+        # Test tenant isolation
+        tenant_manager = TenantCacheManager()
+        tenant1_cache = tenant_manager.get_cache_manager(1)
+        tenant2_cache = tenant_manager.get_cache_manager(2)
+
+        # Different tenants should have different cache managers
+        self.assertIsNot(tenant1_cache, tenant2_cache)
+
+        # Test cache warming
+        cache_warmer = CacheWarmer(cache_manager)
+        warmed = cache_warmer.warm_malaysian_data()
+        self.assertGreater(warmed["sst_rates"], 0)
+
+    def test_cache_error_handling(self):
+        """Test cache error handling."""
+        cache_manager = CacheManager()
+
+        # Test get with non-existent key
+        result = cache_manager.get("nonexistent_key")
+        self.assertIsNone(result)
+
+        # Test get with default value
+        result = cache_manager.get("nonexistent_key", "default")
+        self.assertEqual(result, "default")
+
+        # Test error handling in operations
+        with patch.object(cache_manager, 'set', side_effect=Exception("Cache error")):
+            result = cache_manager.set("test_key", "test_value")
+            self.assertFalse(result)

backend/tests/unit/test_optimization.py

@@ -0,0 +1,682 @@
+"""
+Unit tests for database optimization components.
+
+This module tests the database optimization functionality including query optimization,
+index management, configuration management, and performance monitoring specifically
+designed for the multi-tenant SaaS platform with Malaysian market requirements.
+"""
+
+import unittest
+from unittest.mock import Mock, patch, MagicMock
+from django.test import TestCase, override_settings
+from django.db import connection, models
+from django.core.cache import cache
+from django.utils import timezone
+from django.contrib.auth import get_user_model
+from django_tenants.utils import schema_context
+
+from core.optimization.query_optimization import (
+    DatabaseOptimizer,
+    QueryOptimizer,
+    CacheManager,
+    DatabaseMaintenance,
+    OptimizationLevel,
+    QueryMetrics,
+    IndexRecommendation
+)
+from core.optimization.index_manager import (
+    IndexManager,
+    IndexType,
+    IndexStatus,
+    IndexInfo,
+    IndexRecommendation as IndexRec
+)
+from core.optimization.config import (
+    DatabaseConfig,
+    ConnectionPoolConfig,
+    QueryOptimizationConfig,
+    CacheConfig,
+    MultiTenantConfig,
+    MalaysianConfig,
+    PerformanceConfig,
+    get_config,
+    validate_environment_config
+)
+
+User = get_user_model()
+
+
+class DatabaseOptimizerTests(TestCase):
+    """Test cases for DatabaseOptimizer class."""
+
+    def setUp(self):
+        """Set up test environment."""
+        self.optimizer = DatabaseOptimizer()
+        self.test_tenant = "test_tenant"
+
+    def test_init(self):
+        """Test DatabaseOptimizer initialization."""
+        optimizer = DatabaseOptimizer(self.test_tenant)
+        self.assertEqual(optimizer.tenant_schema, self.test_tenant)
+        self.assertIsInstance(optimizer.query_history, list)
+        self.assertIsInstance(optimizer.optimization_stats, dict)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_monitor_query_context_manager(self, mock_connection):
+        """Test query monitoring context manager."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchone.return_value = ('test_query', 1, 0.5, 10, 1)
+
+        with self.optimizer.monitor_query("test query"):
+            pass
+
+        self.assertEqual(len(self.optimizer.query_history), 1)
+        self.assertEqual(self.optimizer.optimization_stats['queries_analyzed'], 1)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_optimize_tenant_queries(self, mock_connection):
+        """Test tenant query optimization."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchone.return_value = (5,)
+
+        # Create a mock model
+        class TestModel(models.Model):
+            class Meta:
+                app_label = 'test'
+
+        results = self.optimizer.optimize_tenant_queries(TestModel, self.test_tenant)
+
+        self.assertIn('tenant', results)
+        self.assertIn('queries_optimized', results)
+
+    def test_optimize_malaysian_queries(self):
+        """Test Malaysian query optimization."""
+        with patch.object(self.optimizer, '_optimize_sst_queries', return_value=3):
+            with patch.object(self.optimizer, '_optimize_ic_validation', return_value=True):
+                with patch.object(self.optimizer, '_optimize_address_queries', return_value=2):
+                    results = self.optimizer.optimize_malaysian_queries()
+
+        self.assertEqual(results['sst_queries_optimized'], 3)
+        self.assertTrue(results['ic_validation_optimized'])
+        self.assertEqual(results['address_queries_optimized'], 2)
+        self.assertIn('localization_improvements', results)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_analyze_query_performance(self, mock_connection):
+        """Test query performance analysis."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            (100, 0.5, 2),
+            [('public', 'test_table', 10, 100, 5, 50)]
+        ]
+
+        analysis = self.optimizer.analyze_query_performance(24)
+
+        self.assertEqual(analysis['total_queries'], 100)
+        self.assertEqual(analysis['slow_queries'], 2)
+        self.assertEqual(len(analysis['most_used_tables']), 1)
+
+    def test_get_optimization_report(self):
+        """Test optimization report generation."""
+        with patch.object(self.optimizer, 'optimize_malaysian_queries', return_value={}):
+            with patch.object(self.optimizer, 'analyze_query_performance', return_value={}):
+                with patch.object(self.optimizer, '_get_suggested_actions', return_value=[]):
+                    report = self.optimizer.get_optimization_report()
+
+        self.assertIn('optimization_statistics', report)
+        self.assertIn('malaysian_optimizations', report)
+        self.assertIn('suggested_actions', report)
+
+    def test_clear_optimization_history(self):
+        """Test clearing optimization history."""
+        self.optimizer.query_history = [Mock()]
+        self.optimizer.optimization_stats['queries_analyzed'] = 5
+
+        self.optimizer.clear_optimization_history()
+
+        self.assertEqual(len(self.optimizer.query_history), 0)
+        self.assertEqual(self.optimizer.optimization_stats['queries_analyzed'], 0)
+
+
+class QueryOptimizerTests(TestCase):
+    """Test cases for QueryOptimizer static methods."""
+
+    def test_optimize_tenant_filter(self):
+        """Test tenant filter optimization."""
+        queryset = Mock()
+        optimized = QueryOptimizer.optimize_tenant_filter(queryset, 1)
+
+        queryset.filter.assert_called_once_with(tenant_id=1)
+        queryset.select_related.assert_called_once_with('tenant')
+
+    def test_optimize_pagination(self):
+        """Test pagination optimization."""
+        queryset = Mock()
+        optimized = QueryOptimizer.optimize_pagination(queryset, 25)
+
+        queryset.order_by.assert_called_once_with('id')
+        queryset.__getitem__.assert_called_once_with(slice(0, 25))
+
+    def test_optimize_foreign_key_query(self):
+        """Test foreign key query optimization."""
+        queryset = Mock()
+        optimized = QueryOptimizer.optimize_foreign_key_query(queryset, ['user', 'profile'])
+
+        queryset.select_related.assert_called_once_with('user', 'profile')
+
+    def test_optimize_many_to_many_query(self):
+        """Test many-to-many query optimization."""
+        queryset = Mock()
+        optimized = QueryOptimizer.optimize_many_to_many_query(queryset, ['tags', 'categories'])
+
+        queryset.prefetch_related.assert_called_once_with('tags', 'categories')
+
+    def test_optimize_date_range_query(self):
+        """Test date range query optimization."""
+        queryset = Mock()
+        start_date = timezone.now() - timezone.timedelta(days=7)
+        end_date = timezone.now()
+
+        optimized = QueryOptimizer.optimize_date_range_query(
+            queryset, 'created_at', start_date, end_date
+        )
+
+        expected_filter = {
+            'created_at__gte': start_date,
+            'created_at__lte': end_date
+        }
+        queryset.filter.assert_called_once_with(**expected_filter)
+        queryset.order_by.assert_called_once_with('created_at')
+
+    @patch('core.optimization.query_optimization.SearchVector')
+    @patch('core.optimization.query_optimization.SearchQuery')
+    @patch('core.optimization.query_optimization.SearchRank')
+    def test_optimize_full_text_search(self, mock_search_rank, mock_search_query, mock_search_vector):
+        """Test full-text search optimization."""
+        queryset = Mock()
+        mock_search_vector.return_value = Mock()
+        mock_search_query.return_value = Mock()
+        mock_search_rank.return_value = Mock()
+
+        optimized = QueryOptimizer.optimize_full_text_search(
+            queryset, ['title', 'content'], 'search term'
+        )
+
+        queryset.annotate.assert_called()
+        queryset.filter.assert_called()
+        queryset.order_by.assert_called()
+
+
+class CacheManagerTests(TestCase):
+    """Test cases for CacheManager class."""
+
+    def test_get_cache_key(self):
+        """Test cache key generation."""
+        key = CacheManager.get_cache_key("prefix", "arg1", "arg2", 123)
+        self.assertEqual(key, "prefix_arg1_arg2_123")
+
+    def test_cache_query_result(self):
+        """Test caching query results."""
+        cache_key = "test_key"
+        query_result = {"data": "test"}
+
+        CacheManager.cache_query_result(cache_key, query_result, 3600)
+
+        # Mock cache.get to return cached result
+        with patch.object(cache, 'get', return_value=query_result):
+            cached_result = CacheManager.get_cached_result(cache_key)
+            self.assertEqual(cached_result, query_result)
+
+    @patch('core.optimization.query_optimization.cache')
+    def test_invalidate_cache_pattern(self, mock_cache):
+        """Test cache invalidation by pattern."""
+        mock_cache.keys.return_value = ['prefix_1', 'prefix_2', 'other_key']
+
+        CacheManager.invalidate_cache_pattern('prefix_*')
+
+        mock_cache.delete_many.assert_called_once_with(['prefix_1', 'prefix_2'])
+
+
+class DatabaseMaintenanceTests(TestCase):
+    """Test cases for DatabaseMaintenance class."""
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_analyze_tables(self, mock_connection):
+        """Test table analysis."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('public', 'test_table1'),
+            ('public', 'test_table2')
+        ]
+
+        DatabaseMaintenance.analyze_tables()
+
+        self.assertEqual(mock_cursor.execute.call_count, 2)  # SELECT + ANALYZE
+        mock_cursor.execute.assert_any_call("ANALYZE public.test_table1")
+        mock_cursor.execute.assert_any_call("ANALYZE public.test_table2")
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_vacuum_tables(self, mock_connection):
+        """Test table vacuuming."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('public', 'test_table1'),
+            ('public', 'test_table2')
+        ]
+
+        DatabaseMaintenance.vacuum_tables()
+
+        self.assertEqual(mock_cursor.execute.call_count, 2)  # SELECT + VACUUM
+        mock_cursor.execute.assert_any_call("VACUUM ANALYZE public.test_table1")
+        mock_cursor.execute.assert_any_call("VACUUM ANALYZE public.test_table2")
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_get_table_sizes(self, mock_connection):
+        """Test getting table sizes."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('public', 'test_table1', '10 MB', 10485760),
+            ('public', 'test_table2', '5 MB', 5242880)
+        ]
+
+        sizes = DatabaseMaintenance.get_table_sizes()
+
+        self.assertEqual(len(sizes), 2)
+        self.assertEqual(sizes[0]['table'], 'test_table1')
+        self.assertEqual(sizes[0]['size'], '10 MB')
+        self.assertEqual(sizes[0]['size_bytes'], 10485760)
+
+
+class IndexManagerTests(TestCase):
+    """Test cases for IndexManager class."""
+
+    def setUp(self):
+        """Set up test environment."""
+        self.manager = IndexManager(self.test_tenant)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_get_all_indexes(self, mock_connection):
+        """Test getting all indexes."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('idx_test', 'test_table', 'btree', False, False, 'CREATE INDEX idx_test ON test_table (id)', 1024, 'test_tenant')
+        ]
+
+        indexes = self.manager.get_all_indexes()
+
+        self.assertEqual(len(indexes), 1)
+        self.assertIsInstance(indexes[0], IndexInfo)
+        self.assertEqual(indexes[0].name, 'idx_test')
+        self.assertEqual(indexes[0].table_name, 'test_table')
+
+    def test_extract_column_names(self):
+        """Test extracting column names from index definition."""
+        definition = "CREATE INDEX idx_test ON test_table (id, name, created_at)"
+        columns = self.manager._extract_column_names(definition)
+
+        self.assertEqual(columns, ['id', 'name', 'created_at'])
+
+    @patch('core.optimization.index_manager.connection')
+    def test_analyze_index_performance(self, mock_connection):
+        """Test index performance analysis."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('test_table1', 5000, 100000, 1024 * 1024 * 10),
+            ('test_table2', 1000, 50000, 1024 * 1024 * 5)
+        ]
+
+        analysis = self.manager.analyze_index_performance()
+
+        self.assertIn('total_indexes', analysis)
+        self.assertIn('unused_indexes', analysis)
+        self.assertIn('recommendations', analysis)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_create_index(self, mock_connection):
+        """Test index creation."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        index_name = self.manager.create_index(
+            table_name='test_table',
+            columns=['id', 'name'],
+            index_type=IndexType.BTREE,
+            unique=True
+        )
+
+        self.assertEqual(index_name, 'unq_test_table_id_name')
+        mock_cursor.execute.assert_called_once()
+        self.assertEqual(self.manager.stats['indexes_created'], 1)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_drop_index(self, mock_connection):
+        """Test index dropping."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        result = self.manager.drop_index('test_index')
+
+        self.assertTrue(result)
+        mock_cursor.execute.assert_called_once()
+        self.assertEqual(self.manager.stats['indexes_dropped'], 1)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_rebuild_index(self, mock_connection):
+        """Test index rebuilding."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        result = self.manager.rebuild_index('test_index')
+
+        self.assertTrue(result)
+        mock_cursor.execute.assert_called_once_with("REINDEX INDEX test_index")
+        self.assertEqual(self.manager.stats['indexes_rebuilt'], 1)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_create_malaysian_indexes(self, mock_connection):
+        """Test creating Malaysian-specific indexes."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        created = self.manager.create_malaysian_indexes()
+
+        self.assertIsInstance(created, list)
+        # Should create multiple Malaysian indexes
+        self.assertGreater(len(created), 0)
+
+    @patch('core.optimization.index_manager.connection')
+    def test_get_index_statistics(self, mock_connection):
+        """Test getting index statistics."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            ('btree', 5),
+            ('hash', 2),
+            ('active', 6),
+            ('inactive', 1)
+        ]
+
+        stats = self.manager.get_index_statistics()
+
+        self.assertIn('total_indexes', stats)
+        self.assertIn('index_types', stats)
+        self.assertIn('status_distribution', stats)
+        self.assertEqual(stats['index_types']['btree'], 5)
+        self.assertEqual(stats['index_types']['hash'], 2)
+
+
+class DatabaseConfigTests(TestCase):
+    """Test cases for DatabaseConfig class."""
+
+    def test_production_config(self):
+        """Test production configuration."""
+        config = DatabaseConfig("production")
+
+        self.assertEqual(config.environment, "production")
+        self.assertIsInstance(config.connection_pool, ConnectionPoolConfig)
+        self.assertIsInstance(config.query_optimization, QueryOptimizationConfig)
+        self.assertIsInstance(config.cache, CacheConfig)
+        self.assertIsInstance(config.multi_tenant, MultiTenantConfig)
+        self.assertIsInstance(config.malaysian, MalaysianConfig)
+        self.assertIsInstance(config.performance, PerformanceConfig)
+
+        # Check production-specific settings
+        self.assertGreater(config.connection_pool.max_connections, 50)
+        self.assertTrue(config.performance.enable_connection_pooling)
+        self.assertTrue(config.performance.enable_query_optimization)
+
+    def test_staging_config(self):
+        """Test staging configuration."""
+        config = DatabaseConfig("staging")
+
+        self.assertEqual(config.environment, "staging")
+        # Should be less aggressive than production
+        self.assertLess(config.connection_pool.max_connections, 200)
+        self.assertGreater(config.query_optimization.slow_query_threshold, 0.5)
+
+    def test_development_config(self):
+        """Test development configuration."""
+        config = DatabaseConfig("development")
+
+        self.assertEqual(config.environment, "development")
+        # Should have minimal optimization for development
+        self.assertFalse(config.performance.enable_connection_pooling)
+        self.assertFalse(config.performance.enable_query_optimization)
+
+    def test_get_django_database_config(self):
+        """Test Django database configuration generation."""
+        config = DatabaseConfig("production")
+        db_config = config.get_django_database_config()
+
+        self.assertIn('default', db_config)
+        self.assertIn('ENGINE', db_config['default'])
+        self.assertIn('OPTIONS', db_config['default'])
+        self.assertEqual(db_config['default']['ENGINE'], 'django_tenants.postgresql_backend')
+
+    def test_get_django_cache_config(self):
+        """Test Django cache configuration generation."""
+        config = DatabaseConfig("production")
+        cache_config = config.get_django_cache_config()
+
+        self.assertIn('default', cache_config)
+        self.assertIn('tenant_cache', cache_config)
+        self.assertIn('malaysian_cache', cache_config)
+
+    def test_get_postgresql_settings(self):
+        """Test PostgreSQL settings generation."""
+        config = DatabaseConfig("production")
+        settings = config.get_postgresql_settings()
+
+        self.assertIsInstance(settings, list)
+        self.assertGreater(len(settings), 0)
+        # Should contain performance-related settings
+        settings_str = ' '.join(settings)
+        self.assertIn('shared_buffers', settings_str)
+        self.assertIn('effective_cache_size', settings_str)
+
+    def test_validate_configuration(self):
+        """Test configuration validation."""
+        config = DatabaseConfig("production")
+        warnings = config.validate_configuration()
+
+        self.assertIsInstance(warnings, list)
+        # Should not have warnings for valid config
+        # But will accept empty list as valid
+
+    def test_get_performance_recommendations(self):
+        """Test performance recommendations."""
+        config = DatabaseConfig("production")
+        recommendations = config.get_performance_recommendations()
+
+        self.assertIsInstance(recommendations, list)
+        # Should have recommendations for production
+        self.assertGreater(len(recommendations), 0)
+
+
+class ConfigFactoryTests(TestCase):
+    """Test cases for configuration factory functions."""
+
+    def test_get_config(self):
+        """Test configuration factory function."""
+        config = get_config("production")
+        self.assertIsInstance(config, DatabaseConfig)
+        self.assertEqual(config.environment, "production")
+
+    def test_get_production_config(self):
+        """Test production configuration factory."""
+        config = get_production_config()
+        self.assertIsInstance(config, DatabaseConfig)
+        self.assertEqual(config.environment, "production")
+
+    def test_get_staging_config(self):
+        """Test staging configuration factory."""
+        config = get_staging_config()
+        self.assertIsInstance(config, DatabaseConfig)
+        self.assertEqual(config.environment, "staging")
+
+    def test_get_development_config(self):
+        """Test development configuration factory."""
+        config = get_development_config()
+        self.assertIsInstance(config, DatabaseConfig)
+        self.assertEqual(config.environment, "development")
+
+    @patch('core.optimization.config.get_config')
+    def test_validate_environment_config(self, mock_get_config):
+        """Test environment configuration validation."""
+        mock_config = Mock()
+        mock_config.validate_configuration.return_value = []
+        mock_get_config.return_value = mock_config
+
+        result = validate_environment_config("production")
+
+        self.assertTrue(result)
+        mock_config.validate_configuration.assert_called_once()
+
+
+class IntegrationTests(TestCase):
+    """Integration tests for optimization components."""
+
+    @override_settings(CACHES={
+        'default': {
+            'BACKEND': 'django.core.cache.backends.dummy.DummyCache'
+        }
+    })
+    def test_cache_manager_integration(self):
+        """Test CacheManager integration with Django cache."""
+        cache_key = CacheManager.get_cache_key("test", "integration")
+        test_data = {"key": "value"}
+
+        CacheManager.cache_query_result(cache_key, test_data)
+        cached_data = CacheManager.get_cached_result(cache_key)
+
+        self.assertEqual(cached_data, test_data)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_database_optimizer_integration(self, mock_connection):
+        """Test DatabaseOptimizer integration."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchall.return_value = [
+            (100, 0.5, 2),
+            [('public', 'test_table', 10, 100, 5, 50)]
+        ]
+
+        optimizer = DatabaseOptimizer()
+        analysis = optimizer.analyze_query_performance()
+
+        self.assertEqual(analysis['total_queries'], 100)
+        self.assertEqual(analysis['slow_queries'], 2)
+
+    def test_query_optimizer_integration(self):
+        """Test QueryOptimizer integration with mock querysets."""
+        # This test uses mock querysets to test optimization logic
+        queryset = Mock()
+        optimized = QueryOptimizer.optimize_tenant_filter(queryset, 1)
+
+        queryset.filter.assert_called_with(tenant_id=1)
+        queryset.select_related.assert_called_with('tenant')
+
+
+class MalaysianOptimizationTests(TestCase):
+    """Test cases for Malaysian-specific optimizations."""
+
+    def setUp(self):
+        """Set up test environment."""
+        self.optimizer = DatabaseOptimizer()
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_malaysian_sst_optimization(self, mock_connection):
+        """Test SST optimization for Malaysian market."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        result = self.optimizer._optimize_sst_queries()
+
+        self.assertIsInstance(result, int)
+        self.assertGreaterEqual(result, 0)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_malaysian_ic_validation_optimization(self, mock_connection):
+        """Test IC validation optimization for Malaysian market."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        result = self.optimizer._optimize_ic_validation()
+
+        self.assertIsInstance(result, bool)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_malaysian_address_optimization(self, mock_connection):
+        """Test address optimization for Malaysian market."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+
+        result = self.optimizer._optimize_address_queries()
+
+        self.assertIsInstance(result, int)
+        self.assertGreaterEqual(result, 0)
+
+    def test_malaysian_config(self):
+        """Test Malaysian configuration settings."""
+        config = DatabaseConfig("production")
+
+        self.assertEqual(config.malaysian.timezone, "Asia/Kuala_Lumpur")
+        self.assertEqual(config.malaysian.locale, "ms_MY")
+        self.assertEqual(config.malaysian.currency, "MYR")
+        self.assertTrue(config.malaysian.enable_local_caching)
+        self.assertTrue(config.malaysian.malaysian_indexes_enabled)
+
+
+class PerformanceTests(TestCase):
+    """Performance tests for optimization components."""
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_query_monitoring_performance(self, mock_connection):
+        """Test performance of query monitoring."""
+        mock_cursor = Mock()
+        mock_connection.cursor.return_value.__enter__.return_value = mock_cursor
+        mock_cursor.fetchone.return_value = ('test_query', 1, 0.1, 10, 1)
+
+        import time
+        start_time = time.time()
+
+        # Monitor multiple queries
+        for i in range(100):
+            with self.optimizer.monitor_query(f"test query {i}"):
+                pass
+
+        end_time = time.time()
+        execution_time = end_time - start_time
+
+        # Should be fast (less than 1 second for 100 queries)
+        self.assertLess(execution_time, 1.0)
+        self.assertEqual(len(self.optimizer.query_history), 100)
+
+    @patch('core.optimization.query_optimization.connection')
+    def test_cache_manager_performance(self, mock_connection):
+        """Test performance of cache operations."""
+        import time
+        start_time = time.time()
+
+        # Perform multiple cache operations
+        for i in range(1000):
+            key = CacheManager.get_cache_key("perf_test", i)
+            CacheManager.cache_query_result(key, f"value_{i}")
+
+        end_time = time.time()
+        execution_time = end_time - start_time
+
+        # Should be fast (less than 1 second for 1000 operations)
+        self.assertLess(execution_time, 1.0)
+
+
+if __name__ == '__main__':
+    unittest.main()

backend/tests/unit/utils/test_helpers.py

@@ -0,0 +1,461 @@
+"""
+Unit tests for General Helper Utilities
+
+Tests for general utility functions:
+- Date/time helpers
+- String helpers
+- Number helpers
+- File helpers
+- Security helpers
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.utils import timezone
+from datetime import date, datetime, time, timedelta
+from decimal import Decimal
+import hashlib
+import json
+
+from backend.src.core.utils.helpers import (
+    format_datetime,
+    parse_date_string,
+    generate_unique_id,
+    sanitize_filename,
+    calculate_percentage,
+    format_currency,
+    truncate_text,
+    validate_email,
+    generate_random_string,
+    hash_password,
+    verify_password,
+    get_file_extension,
+    format_file_size,
+    is_valid_json,
+    flatten_dict,
+    merge_dicts,
+    retry_function,
+    cache_result
+)
+
+
+class HelperUtilitiesTest(TestCase):
+    """Test cases for helper utilities"""
+
+    def test_format_datetime(self):
+        """Test datetime formatting"""
+        test_datetime = datetime(2024, 1, 15, 14, 30, 45, tzinfo=timezone.utc)
+
+        # Test default formatting
+        formatted = format_datetime(test_datetime)
+        self.assertIn('2024', formatted)
+        self.assertIn('14:30', formatted)
+
+        # Test custom formatting
+        custom_format = format_datetime(test_datetime, '%Y-%m-%d')
+        self.assertEqual(custom_format, '2024-01-15')
+
+        # Test timezone conversion
+        local_format = format_datetime(test_datetime, timezone_name='Asia/Kuala_Lumpur')
+        self.assertIn('22:30', local_format)  # UTC+8
+
+    def test_parse_date_string(self):
+        """Test date string parsing"""
+        test_cases = [
+            {'input': '2024-01-15', 'expected': date(2024, 1, 15)},
+            {'input': '15/01/2024', 'expected': date(2024, 1, 15)},
+            {'input': '01-15-2024', 'expected': date(2024, 1, 15)},
+            {'input': '20240115', 'expected': date(2024, 1, 15)},
+        ]
+
+        for case in test_cases:
+            result = parse_date_string(case['input'])
+            self.assertEqual(result, case['expected'])
+
+    def test_parse_date_string_invalid(self):
+        """Test invalid date string parsing"""
+        invalid_dates = [
+            'invalid-date',
+            '2024-13-01',  # Invalid month
+            '2024-02-30',  # Invalid day
+            '2024/02/30',  # Invalid format
+        ]
+
+        for date_str in invalid_dates:
+            with self.assertRaises(Exception):
+                parse_date_string(date_str)
+
+    def test_generate_unique_id(self):
+        """Test unique ID generation"""
+        # Test default generation
+        id1 = generate_unique_id()
+        id2 = generate_unique_id()
+        self.assertNotEqual(id1, id2)
+        self.assertEqual(len(id1), 36)  # UUID length
+
+        # Test with prefix
+        prefixed_id = generate_unique_id(prefix='USR')
+        self.assertTrue(prefixed_id.startswith('USR_'))
+
+        # Test with custom length
+        short_id = generate_unique_id(length=8)
+        self.assertEqual(len(short_id), 8)
+
+    def test_sanitize_filename(self):
+        """Test filename sanitization"""
+        test_cases = [
+            {
+                'input': 'test file.txt',
+                'expected': 'test_file.txt'
+            },
+            {
+                'input': 'my*document?.pdf',
+                'expected': 'my_document.pdf'
+            },
+            {
+                'input': '  spaces  file  .jpg  ',
+                'expected': 'spaces_file.jpg'
+            },
+            {
+                'input': '../../../malicious/path.txt',
+                'expected': 'malicious_path.txt'
+            }
+        ]
+
+        for case in test_cases:
+            result = sanitize_filename(case['input'])
+            self.assertEqual(result, case['expected'])
+
+    def test_calculate_percentage(self):
+        """Test percentage calculation"""
+        test_cases = [
+            {'part': 50, 'total': 100, 'expected': 50.0},
+            {'part': 25, 'total': 200, 'expected': 12.5},
+            {'part': 0, 'total': 100, 'expected': 0.0},
+            {'part': 100, 'total': 100, 'expected': 100.0},
+        ]
+
+        for case in test_cases:
+            result = calculate_percentage(case['part'], case['total'])
+            self.assertEqual(result, case['expected'])
+
+    def test_calculate_percentage_invalid(self):
+        """Test percentage calculation with invalid inputs"""
+        # Division by zero
+        with self.assertRaises(Exception):
+            calculate_percentage(50, 0)
+
+        # Negative values
+        with self.assertRaises(Exception):
+            calculate_percentage(-10, 100)
+
+    def test_format_currency(self):
+        """Test currency formatting"""
+        amount = Decimal('1234.56')
+
+        # Test default formatting (MYR)
+        formatted = format_currency(amount)
+        self.assertEqual(formatted, 'RM 1,234.56')
+
+        # Test different currency
+        usd_formatted = format_currency(amount, currency='USD')
+        self.assertEqual(usd_formatted, '$ 1,234.56')
+
+        # Test custom locale
+        custom_locale = format_currency(amount, locale='en_US')
+        self.assertIn('$', custom_locale)
+
+        # Test no decimals
+        no_decimals = format_currency(amount, decimals=0)
+        self.assertEqual(no_decimals, 'RM 1,235')
+
+    def test_truncate_text(self):
+        """Test text truncation"""
+        text = "This is a long text that needs to be truncated"
+
+        # Test basic truncation
+        truncated = truncate_text(text, 20)
+        self.assertEqual(len(truncated), 20)
+        self.assertTrue(truncated.endswith('...'))
+
+        # Test with custom suffix
+        custom_suffix = truncate_text(text, 15, suffix=' [more]')
+        self.assertTrue(custom_suffix.endswith(' [more]'))
+
+        # Test text shorter than limit
+        short_text = "Short text"
+        result = truncate_text(short_text, 20)
+        self.assertEqual(result, short_text)
+
+    def test_validate_email(self):
+        """Test email validation"""
+        valid_emails = [
+            'user@example.com',
+            'test.email+tag@domain.co.uk',
+            'user_name@sub.domain.com',
+            '123user@example.org'
+        ]
+
+        invalid_emails = [
+            'invalid-email',
+            '@example.com',
+            'user@',
+            'user@.com',
+            'user..name@example.com',
+            'user@example..com'
+        ]
+
+        for email in valid_emails:
+            self.assertTrue(validate_email(email))
+
+        for email in invalid_emails:
+            self.assertFalse(validate_email(email))
+
+    def test_generate_random_string(self):
+        """Test random string generation"""
+        # Test default length
+        random_str = generate_random_string()
+        self.assertEqual(len(random_str), 12)
+
+        # Test custom length
+        custom_length = generate_random_string(length=20)
+        self.assertEqual(len(custom_length), 20)
+
+        # Test different character sets
+        numeric = generate_random_string(length=10, chars='0123456789')
+        self.assertTrue(numeric.isdigit())
+
+        # Test uniqueness
+        str1 = generate_random_string(length=20)
+        str2 = generate_random_string(length=20)
+        self.assertNotEqual(str1, str2)
+
+    def test_hash_password(self):
+        """Test password hashing"""
+        password = 'test_password_123'
+
+        # Test password hashing
+        hashed = hash_password(password)
+        self.assertNotEqual(hashed, password)
+        self.assertIn('$', hashed)  # bcrypt hash format
+
+        # Test same password produces different hashes (salt)
+        hashed2 = hash_password(password)
+        self.assertNotEqual(hashed, hashed2)
+
+    def test_verify_password(self):
+        """Test password verification"""
+        password = 'test_password_123'
+        hashed = hash_password(password)
+
+        # Test correct password
+        self.assertTrue(verify_password(password, hashed))
+
+        # Test incorrect password
+        self.assertFalse(verify_password('wrong_password', hashed))
+
+        # Test invalid hash
+        self.assertFalse(verify_password(password, 'invalid_hash'))
+
+    def test_get_file_extension(self):
+        """Test file extension extraction"""
+        test_cases = [
+            {'input': 'document.pdf', 'expected': '.pdf'},
+            {'input': 'image.JPG', 'expected': '.jpg'},
+            {'input': 'archive.tar.gz', 'expected': '.gz'},
+            {'input': 'no_extension', 'expected': ''},
+            {'input': '.hidden_file', 'expected': ''},
+        ]
+
+        for case in test_cases:
+            result = get_file_extension(case['input'])
+            self.assertEqual(result.lower(), case['expected'].lower())
+
+    def test_format_file_size(self):
+        """Test file size formatting"""
+        test_cases = [
+            {'bytes': 500, 'expected': '500 B'},
+            {'bytes': 1024, 'expected': '1 KB'},
+            {'bytes': 1536, 'expected': '1.5 KB'},
+            {'bytes': 1048576, 'expected': '1 MB'},
+            {'bytes': 1073741824, 'expected': '1 GB'},
+            {'bytes': 1099511627776, 'expected': '1 TB'},
+        ]
+
+        for case in test_cases:
+            result = format_file_size(case['bytes'])
+            self.assertEqual(result, case['expected'])
+
+    def test_is_valid_json(self):
+        """Test JSON validation"""
+        valid_jsons = [
+            '{"key": "value"}',
+            '[]',
+            'null',
+            '123',
+            '"string"',
+            '{"nested": {"key": "value"}}'
+        ]
+
+        invalid_jsons = [
+            '{invalid json}',
+            'undefined',
+            'function() {}',
+            '{key: "value"}',  # Unquoted key
+            '["unclosed array"',
+        ]
+
+        for json_str in valid_jsons:
+            self.assertTrue(is_valid_json(json_str))
+
+        for json_str in invalid_jsons:
+            self.assertFalse(is_valid_json(json_str))
+
+    def test_flatten_dict(self):
+        """Test dictionary flattening"""
+        nested_dict = {
+            'user': {
+                'name': 'John',
+                'profile': {
+                    'age': 30,
+                    'city': 'KL'
+                }
+            },
+            'settings': {
+                'theme': 'dark',
+                'notifications': True
+            }
+        }
+
+        flattened = flatten_dict(nested_dict)
+
+        expected_keys = [
+            'user_name',
+            'user_profile_age',
+            'user_profile_city',
+            'settings_theme',
+            'settings_notifications'
+        ]
+
+        for key in expected_keys:
+            self.assertIn(key, flattened)
+
+        self.assertEqual(flattened['user_name'], 'John')
+        self.assertEqual(flattened['user_profile_age'], 30)
+
+    def test_merge_dicts(self):
+        """Test dictionary merging"""
+        dict1 = {'a': 1, 'b': 2, 'c': 3}
+        dict2 = {'b': 20, 'd': 4, 'e': 5}
+
+        merged = merge_dicts(dict1, dict2)
+
+        self.assertEqual(merged['a'], 1)  # From dict1
+        self.assertEqual(merged['b'], 20)  # From dict2 (overwritten)
+        self.assertEqual(merged['c'], 3)   # From dict1
+        self.assertEqual(merged['d'], 4)   # From dict2
+        self.assertEqual(merged['e'], 5)   # From dict2
+
+    def test_retry_function(self):
+        """Test function retry mechanism"""
+        # Test successful execution
+        def successful_function():
+            return "success"
+
+        result = retry_function(successful_function, max_retries=3)
+        self.assertEqual(result, "success")
+
+        # Test function that fails then succeeds
+        call_count = 0
+
+        def flaky_function():
+            nonlocal call_count
+            call_count += 1
+            if call_count < 3:
+                raise Exception("Temporary failure")
+            return "eventual_success"
+
+        result = retry_function(flaky_function, max_retries=5)
+        self.assertEqual(result, "eventual_success")
+        self.assertEqual(call_count, 3)
+
+        # Test function that always fails
+        def failing_function():
+            raise Exception("Permanent failure")
+
+        with self.assertRaises(Exception):
+            retry_function(failing_function, max_retries=3)
+
+    def test_cache_result(self):
+        """Test result caching decorator"""
+        # Create a function that counts calls
+        call_count = 0
+
+        @cache_result(timeout=60)  # 60 second cache
+        def expensive_function(x, y):
+            nonlocal call_count
+            call_count += 1
+            return x + y
+
+        # First call should execute function
+        result1 = expensive_function(2, 3)
+        self.assertEqual(result1, 5)
+        self.assertEqual(call_count, 1)
+
+        # Second call with same arguments should use cache
+        result2 = expensive_function(2, 3)
+        self.assertEqual(result2, 5)
+        self.assertEqual(call_count, 1)  # No additional call
+
+        # Call with different arguments should execute function
+        result3 = expensive_function(3, 4)
+        self.assertEqual(result3, 7)
+        self.assertEqual(call_count, 2)
+
+    def test_decimal_conversion(self):
+        """Test decimal conversion utilities"""
+        # Test string to decimal
+        decimal_value = Decimal('123.45')
+        self.assertEqual(decimal_value, Decimal('123.45'))
+
+        # Test float to decimal (with precision warning)
+        float_value = 123.45
+        decimal_from_float = Decimal(str(float_value))
+        self.assertEqual(decimal_from_float, Decimal('123.45'))
+
+    def test_timezone_handling(self):
+        """Test timezone handling utilities"""
+        # Test timezone aware datetime
+        utc_now = timezone.now()
+        self.assertIsNotNone(utc_now.tzinfo)
+
+        # Test timezone conversion
+        kl_time = format_datetime(utc_now, timezone_name='Asia/Kuala_Lumpur')
+        self.assertIn('+08', kl_time)
+
+    def test_string_manipulation(self):
+        """Test string manipulation utilities"""
+        # Test string cleaning
+        dirty_string = "  Hello   World  \n\t"
+        clean_string = " ".join(dirty_string.split())
+        self.assertEqual(clean_string, "Hello World")
+
+        # Test case conversion
+        test_string = "Hello World"
+        self.assertEqual(test_string.lower(), "hello world")
+        self.assertEqual(test_string.upper(), "HELLO WORLD")
+        self.assertEqual(test_string.title(), "Hello World")
+
+    def test_list_operations(self):
+        """Test list operation utilities"""
+        # Test list deduplication
+        duplicate_list = [1, 2, 2, 3, 4, 4, 5]
+        unique_list = list(set(duplicate_list))
+        self.assertEqual(len(unique_list), 5)
+
+        # Test list sorting
+        unsorted_list = [3, 1, 4, 1, 5, 9, 2, 6]
+        sorted_list = sorted(unsorted_list)
+        self.assertEqual(sorted_list, [1, 1, 2, 3, 4, 5, 6, 9])

backend/tests/unit/utils/test_malaysian_validators.py

@@ -0,0 +1,387 @@
+"""
+Unit tests for Malaysian Validators
+
+Tests for Malaysian-specific validation utilities:
+- IC number validation
+- Phone number validation
+- Business registration validation
+- Address validation
+- SST calculation
+
+Author: Claude
+"""
+
+import pytest
+from django.test import TestCase
+from django.core.exceptions import ValidationError
+
+from backend.src.core.utils.malaysian_validators import (
+    validate_ic_number,
+    validate_phone_number,
+    validate_business_registration,
+    validate_malaysian_address,
+    calculate_sst,
+    validate_postal_code,
+    format_malaysian_phone,
+    get_malaysian_states
+)
+
+
+class MalaysianValidatorsTest(TestCase):
+    """Test cases for Malaysian validators"""
+
+    def test_validate_ic_number_valid(self):
+        """Test valid Malaysian IC number validation"""
+        valid_ic_numbers = [
+            '000101-01-0001',  # Valid format
+            '900101-10-1234',  # Valid format
+            '851231-12-5678',  # Valid format
+        ]
+
+        for ic_number in valid_ic_numbers:
+            result = validate_ic_number(ic_number)
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['normalized'], ic_number)
+
+    def test_validate_ic_number_invalid(self):
+        """Test invalid Malaysian IC number validation"""
+        invalid_ic_numbers = [
+            '123',                    # Too short
+            '000101-01-000',          # Wrong length
+            '000101-01-00012',        # Wrong length
+            '000101-01-000A',         # Contains letter
+            '000101/01/0001',         # Wrong separator
+            '00-01-01-0001',          # Wrong format
+        ]
+
+        for ic_number in invalid_ic_numbers:
+            result = validate_ic_number(ic_number)
+            self.assertFalse(result['is_valid'])
+            self.assertIsNotNone(result.get('error'))
+
+    def test_validate_phone_number_valid(self):
+        """Test valid Malaysian phone number validation"""
+        valid_phones = [
+            '+60123456789',    # Standard mobile
+            '0123456789',      # Mobile without country code
+            '+60312345678',    # Landline
+            '0312345678',      # Landline without country code
+            '+60111234567',    # New mobile prefix
+        ]
+
+        for phone in valid_phones:
+            result = validate_phone_number(phone)
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['type'], 'mobile' if phone.startswith('01') else 'landline')
+
+    def test_validate_phone_number_invalid(self):
+        """Test invalid Malaysian phone number validation"""
+        invalid_phones = [
+            '12345',           # Too short
+            '0123456789A',     # Contains letter
+            '+6512345678',     # Singapore number
+            '123456789012',    # Too long
+            '0112345678',      # Invalid prefix
+        ]
+
+        for phone in invalid_phones:
+            result = validate_phone_number(phone)
+            self.assertFalse(result['is_valid'])
+            self.assertIsNotNone(result.get('error'))
+
+    def test_validate_business_registration_valid(self):
+        """Test valid business registration validation"""
+        valid_registrations = [
+            '202401000001',    # Company registration
+            '001234567-K',     # Business registration
+            'SM1234567-K',     # Small medium enterprise
+        ]
+
+        for reg in valid_registrations:
+            result = validate_business_registration(reg)
+            self.assertTrue(result['is_valid'])
+            self.assertIsNotNone(result.get('type'))
+
+    def test_validate_business_registration_invalid(self):
+        """Test invalid business registration validation"""
+        invalid_registrations = [
+            '123',             # Too short
+            '20240100000',     # Missing check digit
+            '202401000001A',   # Contains letter
+            '0012345678-K',    # Too long
+        ]
+
+        for reg in invalid_registrations:
+            result = validate_business_registration(reg)
+            self.assertFalse(result['is_valid'])
+            self.assertIsNotNone(result.get('error'))
+
+    def test_validate_malaysian_address_valid(self):
+        """Test valid Malaysian address validation"""
+        valid_addresses = [
+            {
+                'address': '123 Test Street',
+                'city': 'Kuala Lumpur',
+                'state': 'KUL',
+                'postal_code': '50000'
+            },
+            {
+                'address': '456 Jalan Merdeka',
+                'city': 'Penang',
+                'state': 'PNG',
+                'postal_code': '10000'
+            }
+        ]
+
+        for address in valid_addresses:
+            result = validate_malaysian_address(address)
+            self.assertTrue(result['is_valid'])
+
+    def test_validate_malaysian_address_invalid(self):
+        """Test invalid Malaysian address validation"""
+        invalid_addresses = [
+            {
+                'address': '',  # Empty address
+                'city': 'Kuala Lumpur',
+                'state': 'KUL',
+                'postal_code': '50000'
+            },
+            {
+                'address': '123 Test Street',
+                'city': '',  # Empty city
+                'state': 'KUL',
+                'postal_code': '50000'
+            },
+            {
+                'address': '123 Test Street',
+                'city': 'Kuala Lumpur',
+                'state': 'XX',  # Invalid state
+                'postal_code': '50000'
+            },
+            {
+                'address': '123 Test Street',
+                'city': 'Kuala Lumpur',
+                'state': 'KUL',
+                'postal_code': '123'  # Invalid postal code
+            }
+        ]
+
+        for address in invalid_addresses:
+            result = validate_malaysian_address(address)
+            self.assertFalse(result['is_valid'])
+            self.assertIsNotNone(result.get('errors'))
+
+    def test_calculate_sst(self):
+        """Test SST calculation"""
+        test_cases = [
+            {'amount': 100.00, 'expected_sst': 6.00},      # 6% SST
+            {'amount': 50.00, 'expected_sst': 3.00},       # 6% SST
+            {'amount': 0.00, 'expected_sst': 0.00},        # Zero amount
+            {'amount': 999.99, 'expected_sst': 59.9994},   # High amount
+        ]
+
+        for case in test_cases:
+            sst_amount = calculate_sst(case['amount'])
+            self.assertAlmostEqual(sst_amount, case['expected_sst'], places=4)
+
+    def test_calculate_sst_invalid(self):
+        """Test SST calculation with invalid inputs"""
+        invalid_cases = [
+            -100.00,   # Negative amount
+            None,      # None value
+            'invalid', # String value
+        ]
+
+        for amount in invalid_cases:
+            with self.assertRaises(Exception):
+                calculate_sst(amount)
+
+    def test_validate_postal_code_valid(self):
+        """Test valid postal code validation"""
+        valid_postal_codes = [
+            '50000',    # KL postal code
+            '10000',    # Penang postal code
+            '80000',    # Johor Bahru postal code
+            '97000',    # Sarawak postal code
+        ]
+
+        for postal_code in valid_postal_codes:
+            result = validate_postal_code(postal_code)
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['state'], result.get('state'))
+
+    def test_validate_postal_code_invalid(self):
+        """Test invalid postal code validation"""
+        invalid_postal_codes = [
+            '1234',     # Too short
+            '123456',   # Too long
+            'ABCDE',    # Contains letters
+            '00000',    # Invalid range
+            '99999',    # Invalid range
+        ]
+
+        for postal_code in invalid_postal_codes:
+            result = validate_postal_code(postal_code)
+            self.assertFalse(result['is_valid'])
+            self.assertIsNotNone(result.get('error'))
+
+    def test_format_malaysian_phone(self):
+        """Test Malaysian phone number formatting"""
+        test_cases = [
+            {'input': '0123456789', 'expected': '+6012-3456789'},
+            {'input': '+60123456789', 'expected': '+6012-3456789'},
+            {'input': '0312345678', 'expected': '+603-12345678'},
+            {'input': '+60312345678', 'expected': '+603-12345678'},
+        ]
+
+        for case in test_cases:
+            formatted = format_malaysian_phone(case['input'])
+            self.assertEqual(formatted, case['expected'])
+
+    def test_format_malaysian_phone_invalid(self):
+        """Test formatting invalid phone numbers"""
+        invalid_phones = [
+            '12345',     # Too short
+            'invalid',   # Non-numeric
+            '6512345678', # Singapore number
+        ]
+
+        for phone in invalid_phones:
+            result = format_malaysian_phone(phone)
+            self.assertEqual(result, phone)  # Should return original if invalid
+
+    def test_get_malaysian_states(self):
+        """Test getting Malaysian states"""
+        states = get_malaysian_states()
+
+        # Check if all expected states are present
+        expected_states = [
+            'Johor', 'Kedah', 'Kelantan', 'Malacca', 'Negeri Sembilan',
+            'Pahang', 'Perak', 'Perlis', 'Penang', 'Sabah', 'Sarawak',
+            'Selangor', 'Terengganu', 'Kuala Lumpur', 'Labuan', 'Putrajaya'
+        ]
+
+        for state in expected_states:
+            self.assertIn(state, states)
+
+        # Check state codes
+        self.assertEqual(states['Kuala Lumpur'], 'KUL')
+        self.assertEqual(states['Penang'], 'PNG')
+        self.assertEqual(states['Johor'], 'JHR')
+
+    def test_ic_number_structure_validation(self):
+        """Test IC number structure validation"""
+        # Test age calculation from IC
+        ic_1990 = '900101-01-0001'  # Born 1990
+        result = validate_ic_number(ic_1990)
+        self.assertTrue(result['is_valid'])
+        self.assertEqual(result['birth_year'], 1990)
+        self.assertEqual(result['birth_date'], '1990-01-01')
+
+        # Test gender from IC (last digit: odd = male, even = female)
+        ic_male = '900101-01-0001'  # Odd last digit
+        ic_female = '900101-01-0002'  # Even last digit
+
+        result_male = validate_ic_number(ic_male)
+        result_female = validate_ic_number(ic_female)
+
+        self.assertEqual(result_male['gender'], 'male')
+        self.assertEqual(result_female['gender'], 'female')
+
+    def test_phone_number_type_detection(self):
+        """Test phone number type detection"""
+        mobile_numbers = [
+            '0123456789',   # Maxis
+            '0198765432',   # Celcom
+            '0162345678',   # DiGi
+            '0181234567',   # U Mobile
+            '01112345678',  # Yes 4G
+        ]
+
+        landline_numbers = [
+            '0312345678',   # KL
+            '0412345678',   # Penang
+            '0512345678',   # Perak
+            '0612345678',   # Melaka
+            '0712345678',   # Johor
+        ]
+
+        for number in mobile_numbers:
+            result = validate_phone_number(number)
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['type'], 'mobile')
+
+        for number in landline_numbers:
+            result = validate_phone_number(number)
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['type'], 'landline')
+
+    def test_business_registration_type_detection(self):
+        """Test business registration type detection"""
+        company_reg = '202401000001'  # Company registration
+        business_reg = '001234567-K'  # Business registration
+        sme_reg = 'SM1234567-K'      # Small medium enterprise
+
+        result_company = validate_business_registration(company_reg)
+        result_business = validate_business_registration(business_reg)
+        result_sme = validate_business_registration(sme_reg)
+
+        self.assertEqual(result_company['type'], 'company')
+        self.assertEqual(result_business['type'], 'business')
+        self.assertEqual(result_sme['type'], 'sme')
+
+    def test_address_component_validation(self):
+        """Test individual address component validation"""
+        # Test state code validation
+        valid_states = ['KUL', 'PNG', 'JHR', 'KDH', 'KTN']
+        invalid_states = ['XX', 'ABC', '123']
+
+        for state in valid_states:
+            address = {
+                'address': '123 Test Street',
+                'city': 'Test City',
+                'state': state,
+                'postal_code': '50000'
+            }
+            result = validate_malaysian_address(address)
+            self.assertTrue(result['is_valid'])
+
+        for state in invalid_states:
+            address = {
+                'address': '123 Test Street',
+                'city': 'Test City',
+                'state': state,
+                'postal_code': '50000'
+            }
+            result = validate_malaysian_address(address)
+            self.assertFalse(result['is_valid'])
+
+    def test_sst_edge_cases(self):
+        """Test SST calculation edge cases"""
+        # Test very small amounts
+        sst_small = calculate_sst(0.01)
+        self.assertAlmostEqual(sst_small, 0.0006, places=4)
+
+        # Test very large amounts
+        sst_large = calculate_sst(1000000.00)
+        self.assertEqual(sst_large, 60000.00)
+
+        # Test decimal places
+        sst_decimal = calculate_sst(123.45)
+        self.assertAlmostEqual(sst_decimal, 7.407, places=4)
+
+    def test_postal_code_state_mapping(self):
+        """Test postal code to state mapping"""
+        # Test known postal code ranges
+        test_cases = [
+            {'postal_code': '50000', 'expected_state': 'KUL'},  # KL
+            {'postal_code': '10000', 'expected_state': 'PNG'},  # Penang
+            {'postal_code': '80000', 'expected_state': 'JHR'},  # Johor
+            {'postal_code': '09000', 'expected_state': 'KDH'},  # Kedah
+            {'postal_code': '98000', 'expected_state': 'SBH'},  # Sabah
+        ]
+
+        for case in test_cases:
+            result = validate_postal_code(case['postal_code'])
+            self.assertTrue(result['is_valid'])
+            self.assertEqual(result['state'], case['expected_state'])