test: migrate backend suites to pytest with module coverage gate

Split backend tests into unit and integration suites, add isolated fixtures and coverage enforcement, and update CI and test documentation. Cover current authentication, content, notification, payment, media, and admin flows; fix behaviors revealed by the new tests. Validate both suites and the per-module gate against local PostgreSQL.

apps/payments/tests/integration/test_payment_models.py

@@ -0,0 +1,148 @@
+import pytest
+import uuid
+from datetime import timedelta
+from types import SimpleNamespace
+from django.core.exceptions import ValidationError
+from django.utils import timezone
+from django.contrib.admin import AdminSite
+from apps.payments.admin import DiscountCodeAdmin
+from apps.payments.models import DiscountCode, Payment
+from apps.payments.resources import DiscountResource, PaymentResource
+from apps.events.models import Event
+from apps.users.models import User
+from ninja.errors import HttpError
+
+class PaymentTestMixin:
+
+    @staticmethod
+    def _create_user(**overrides):
+        data = {'username': f'user_{uuid.uuid4().hex[:6]}', 'email': f'user_{uuid.uuid4().hex[:6]}@example.com', 'mobile': f'09{uuid.uuid4().int % 1000000000:09d}', 'password': 'Test!1234'}
+        data.update(overrides)
+        return User.objects.create_user(**data)
+
+    @staticmethod
+    def _create_event(**overrides):
+        now = timezone.now()
+        defaults = {'title': 'Sample', 'description': 'Desc', 'start_time': now, 'end_time': now + timedelta(hours=2), 'registration_start_date': now - timedelta(days=1), 'registration_end_date': now + timedelta(days=5), 'slug': f'event-{uuid.uuid4().hex[:6]}', 'price': 100000, 'capacity': 10, 'status': Event.StatusChoices.PUBLISHED}
+        defaults.update(overrides)
+        return Event.objects.create(**defaults)
+
+    @staticmethod
+    def _discount_code(**overrides):
+        defaults = {'code': f'CODE{uuid.uuid4().hex[:4]}', 'value': 50, 'is_active': True, 'type': DiscountCode.Type.PERCENT}
+        defaults.update(overrides)
+        return DiscountCode.objects.create(**defaults)
+
+@pytest.mark.django_db
+@pytest.mark.integration
+class TestDiscountCodeModelTests(PaymentTestMixin):
+
+    def setup_method(self):
+        self.event = self._create_event()
+        self.user = self._create_user(is_email_verified=True)
+
+    def test_zero_price_returns_zero_discount(self):
+        event = self._create_event(price=0)
+        code = self._discount_code()
+        code.applicable_events.add(event)
+        assert code.calculate_discount(event, self.user) == (0, 0)
+
+    def test_inactive_raises_error(self):
+        code = self._discount_code(is_active=False)
+        code.applicable_events.add(self.event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_start_date_validation(self):
+        code = self._discount_code(starts_at=timezone.now() + timedelta(days=1))
+        code.applicable_events.add(self.event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_end_date_validation(self):
+        code = self._discount_code(ends_at=timezone.now() - timedelta(days=1))
+        code.applicable_events.add(self.event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_applicable_events_enforcement(self):
+        code = self._discount_code()
+        other_event = self._create_event()
+        code.applicable_events.add(other_event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_min_amount_guard(self):
+        code = self._discount_code(min_amount=200000)
+        code.applicable_events.add(self.event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_usage_limit_total(self):
+        code = self._discount_code(usage_limit_total=1)
+        code.applicable_events.add(self.event)
+        Payment.objects.create(user=self.user, event=self.event, base_amount=self.event.price, amount=self.event.price, discount_amount=0, status=Payment.OrderStatusChoices.PAID, discount_code=code)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_usage_limit_per_user(self):
+        code = self._discount_code(usage_limit_per_user=1)
+        code.applicable_events.add(self.event)
+        Payment.objects.create(user=self.user, event=self.event, base_amount=self.event.price, amount=self.event.price, discount_amount=0, status=Payment.OrderStatusChoices.PENDING, discount_code=code)
+        with pytest.raises(HttpError):
+            code.calculate_discount(self.event, self.user)
+
+    def test_final_price_below_min_post_discount(self):
+        event = self._create_event(price=15000)
+        code = self._discount_code(value=80)
+        code.applicable_events.add(event)
+        with pytest.raises(HttpError):
+            code.calculate_discount(event, self.user)
+
+    def test_fixed_discount_type(self):
+        code = self._discount_code(type=DiscountCode.Type.FIXED, value=5000)
+        code.applicable_events.add(self.event)
+        final, disc = code.calculate_discount(self.event, self.user)
+        assert disc == 5000
+        assert final == self.event.price - 5000
+
+@pytest.mark.django_db
+@pytest.mark.integration
+class TestPaymentModelAndResourceTests(PaymentTestMixin):
+
+    def setup_method(self):
+        self.event = self._create_event()
+        self.user = self._create_user(is_email_verified=True)
+
+    def test_payment_clean_validates_amount(self):
+        payment = Payment(user=self.user, event=self.event, base_amount=1000, amount=500, discount_amount=400, status=Payment.OrderStatusChoices.INIT)
+        with pytest.raises(ValidationError):
+            payment.full_clean()
+
+    def test_payment_resource_defers_user_event(self):
+        payment = Payment.objects.create(user=self.user, event=self.event, base_amount=1000, amount=1000, discount_amount=0, status=Payment.OrderStatusChoices.INIT)
+        resource = PaymentResource()
+        user_cell = resource.fields['user'].widget.clean(self.user.username, None)
+        assert user_cell == self.user
+        event_cell = resource.fields['event'].widget.clean(self.event.title, None)
+        assert event_cell == self.event
+
+    def test_discount_resource_expands_events(self):
+        resource = DiscountResource()
+        widget = resource.fields['event'].widget
+        assert widget.separator == '||'
+
+@pytest.mark.django_db
+@pytest.mark.integration
+class TestDiscountCodeAdminTests(PaymentTestMixin):
+
+    def setup_method(self):
+        self.admin = DiscountCodeAdmin(DiscountCode, AdminSite())
+
+    def test_deactivate_codes_action(self):
+        code = self._discount_code()
+        queryset = DiscountCode.objects.filter(pk=code.pk)
+        request = SimpleNamespace(_messages=SimpleNamespace(add=lambda *args, **kwargs: None))
+        self.admin.deactivate_codes(request, queryset)
+        code.refresh_from_db()
+        assert not code.is_active