affaan-m/everything-claude-code/django-tdd

# Step 1: RED - Write failing test
def test_user_creation():
    user = User.objects.create_user(email='test@example.com', password='testpass123')
    assert user.email == 'test@example.com'
    assert user.check_password('testpass123')
    assert not user.is_staff
# Step 2: GREEN - Make test pass
# Create User model or factory
# Step 3: REFACTOR - Improve while keeping tests green

# pytest.ini
[pytest]
DJANGO_SETTINGS_MODULE = config.settings.test
testpaths = tests
python_files = test_*.py
python_classes = Test*
python_functions = test_*
addopts =
    --reuse-db
    --nomigrations
    --cov=apps
    --cov-report=html
    --cov-report=term-missing
    --strict-markers
markers =
    slow: marks tests as slow
    integration: marks tests as integration tests

# config/settings/test.py
from .base import *
DEBUG = True
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': ':memory:',
    }
}
# Disable migrations for speed
class DisableMigrations:
    def __contains__(self, item):
        return True
    def __getitem__(self, item):
        return None
MIGRATION_MODULES = DisableMigrations()
# Faster password hashing
PASSWORD_HASHERS = [
    'django.contrib.auth.hashers.MD5PasswordHasher',
]
# Email backend
EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'
# Celery always eager
CELERY_TASK_ALWAYS_EAGER = True
CELERY_TASK_EAGER_PROPAGATES = True

# tests/conftest.py
import pytest
from django.utils import timezone
from django.contrib.auth import get_user_model
User = get_user_model()
@pytest.fixture(autouse=True)
def timezone_settings(settings):
    """Ensure consistent timezone."""
    settings.TIME_ZONE = 'UTC'
@pytest.fixture
def user(db):
    """Create a test user."""
    return User.objects.create_user(
        email='test@example.com',
        password='testpass123',
        username='testuser'
    )
@pytest.fixture
def admin_user(db):
    """Create an admin user."""
    return User.objects.create_superuser(
        email='admin@example.com',
        password='adminpass123',
        username='admin'
    )
@pytest.fixture
def authenticated_client(client, user):
    """Return authenticated client."""
    client.force_login(user)
    return client
@pytest.fixture
def api_client():
    """Return DRF API client."""
    from rest_framework.test import APIClient
    return APIClient()
@pytest.fixture
def authenticated_api_client(api_client, user):
    """Return authenticated API client."""
    api_client.force_authenticate(user=user)
    return api_client

# tests/factories.py
import factory
from factory import fuzzy
from datetime import datetime, timedelta
from django.contrib.auth import get_user_model
from apps.products.models import Product, Category
User = get_user_model()
class UserFactory(factory.django.DjangoModelFactory):
    """Factory for User model."""
    class Meta:
        model = User
    email = factory.Sequence(lambda n: f"user{n}@example.com")
    username = factory.Sequence(lambda n: f"user{n}")
    password = factory.PostGenerationMethodCall('set_password', 'testpass123')
    first_name = factory.Faker('first_name')
    last_name = factory.Faker('last_name')
    is_active = True
class CategoryFactory(factory.django.DjangoModelFactory):
    """Factory for Category model."""
    class Meta:
        model = Category
    name = factory.Faker('word')
    slug = factory.LazyAttribute(lambda obj: obj.name.lower())
    description = factory.Faker('text')
class ProductFactory(factory.django.DjangoModelFactory):
    """Factory for Product model."""
    class Meta:
        model = Product
    name = factory.Faker('sentence', nb_words=3)
    slug = factory.LazyAttribute(lambda obj: obj.name.lower().replace(' ', '-'))
    description = factory.Faker('text')
    price = fuzzy.FuzzyDecimal(10.00, 1000.00, 2)
    stock = fuzzy.FuzzyInteger(0, 100)
    is_active = True
    category = factory.SubFactory(CategoryFactory)
    created_by = factory.SubFactory(UserFactory)
    @factory.post_generation
    def tags(self, create, extracted, **kwargs):
        """Add tags to product."""
        if not create:
            return
        if extracted:
            for tag in extracted:
                self.tags.add(tag)

# tests/test_models.py
import pytest
from tests.factories import ProductFactory, UserFactory
def test_product_creation():
    """Test product creation using factory."""
    product = ProductFactory(price=100.00, stock=50)
    assert product.price == 100.00
    assert product.stock == 50
    assert product.is_active is True
def test_product_with_tags():
    """Test product with tags."""
    tags = [TagFactory(name='electronics'), TagFactory(name='new')]
    product = ProductFactory(tags=tags)
    assert product.tags.count() == 2
def test_multiple_products():
    """Test creating multiple products."""
    products = ProductFactory.create_batch(10)
    assert len(products) == 10

# tests/test_models.py
import pytest
from django.core.exceptions import ValidationError
from tests.factories import UserFactory, ProductFactory
class TestUserModel:
    """Test User model."""
    def test_create_user(self, db):
        """Test creating a regular user."""
        user = UserFactory(email='test@example.com')
        assert user.email == 'test@example.com'
        assert user.check_password('testpass123')
        assert not user.is_staff
        assert not user.is_superuser
    def test_create_superuser(self, db):
        """Test creating a superuser."""
        user = UserFactory(
            email='admin@example.com',
            is_staff=True,
            is_superuser=True
        )
        assert user.is_staff
        assert user.is_superuser
    def test_user_str(self, db):
        """Test user string representation."""
        user = UserFactory(email='test@example.com')
        assert str(user) == 'test@example.com'
class TestProductModel:
    """Test Product model."""
    def test_product_creation(self, db):
        """Test creating a product."""
        product = ProductFactory()
        assert product.id is not None
        assert product.is_active is True
        assert product.created_at is not None
    def test_product_slug_generation(self, db):
        """Test automatic slug generation."""
        product = ProductFactory(name='Test Product')
        assert product.slug == 'test-product'
    def test_product_price_validation(self, db):
        """Test price cannot be negative."""
        product = ProductFactory(price=-10)
        with pytest.raises(ValidationError):
            product.full_clean()
    def test_product_manager_active(self, db):
        """Test active manager method."""
        ProductFactory.create_batch(5, is_active=True)
        ProductFactory.create_batch(3, is_active=False)
        active_count = Product.objects.active().count()
        assert active_count == 5
    def test_product_stock_management(self, db):
        """Test stock management."""
        product = ProductFactory(stock=10)
        product.reduce_stock(5)
        product.refresh_from_db()
        assert product.stock == 5
        with pytest.raises(ValueError):
            product.reduce_stock(10)  # Not enough stock

# tests/test_views.py
import pytest
from django.urls import reverse
from tests.factories import ProductFactory, UserFactory
class TestProductViews:
    """Test product views."""
    def test_product_list(self, client, db):
        """Test product list view."""
        ProductFactory.create_batch(10)
        response = client.get(reverse('products:list'))
        assert response.status_code == 200
        assert len(response.context['products']) == 10
    def test_product_detail(self, client, db):
        """Test product detail view."""
        product = ProductFactory()
        response = client.get(reverse('products:detail', kwargs={'slug': product.slug}))
        assert response.status_code == 200
        assert response.context['product'] == product
    def test_product_create_requires_login(self, client, db):
        """Test product creation requires authentication."""
        response = client.get(reverse('products:create'))
        assert response.status_code == 302
        assert response.url.startswith('/accounts/login/')
    def test_product_create_authenticated(self, authenticated_client, db):
        """Test product creation as authenticated user."""
        response = authenticated_client.get(reverse('products:create'))
        assert response.status_code == 200
    def test_product_create_post(self, authenticated_client, db, category):
        """Test creating a product via POST."""
        data = {
            'name': 'Test Product',
            'description': 'A test product',
            'price': '99.99',
            'stock': 10,
            'category': category.id,
        }
        response = authenticated_client.post(reverse('products:create'), data)
        assert response.status_code == 302
        assert Product.objects.filter(name='Test Product').exists()

# tests/test_serializers.py
import pytest
from rest_framework.exceptions import ValidationError
from apps.products.serializers import ProductSerializer
from tests.factories import ProductFactory
class TestProductSerializer:
    """Test ProductSerializer."""
    def test_serialize_product(self, db):
        """Test serializing a product."""
        product = ProductFactory()
        serializer = ProductSerializer(product)
        data = serializer.data
        assert data['id'] == product.id
        assert data['name'] == product.name
        assert data['price'] == str(product.price)
    def test_deserialize_product(self, db):
        """Test deserializing product data."""
        data = {
            'name': 'Test Product',
            'description': 'Test description',
            'price': '99.99',
            'stock': 10,
            'category': 1,
        }
        serializer = ProductSerializer(data=data)
        assert serializer.is_valid()
        product = serializer.save()
        assert product.name == 'Test Product'
        assert float(product.price) == 99.99
    def test_price_validation(self, db):
        """Test price validation."""
        data = {
            'name': 'Test Product',
            'price': '-10.00',
            'stock': 10,
        }
        serializer = ProductSerializer(data=data)
        assert not serializer.is_valid()
        assert 'price' in serializer.errors
    def test_stock_validation(self, db):
        """Test stock cannot be negative."""
        data = {
            'name': 'Test Product',
            'price': '99.99',
            'stock': -5,
        }
        serializer = ProductSerializer(data=data)
        assert not serializer.is_valid()
        assert 'stock' in serializer.errors

# tests/test_api.py
import pytest
from rest_framework.test import APIClient
from rest_framework import status
from django.urls import reverse
from tests.factories import ProductFactory, UserFactory
class TestProductAPI:
    """Test Product API endpoints."""
    @pytest.fixture
    def api_client(self):
        """Return API client."""
        return APIClient()