django-tdd

name	django-tdd
description	Django testing with pytest-django, factory_boy, mocking, and coverage. Use when writing Django tests, doing TDD in Django, testing DRF APIs, or setting up pytest-django and factory_boy.
origin	MCC

Django Testing with TDD

Test-driven development for Django applications using pytest, factory_boy, and Django REST Framework.

When to Activate

• Writing new Django applications
• Implementing Django REST Framework APIs
• Testing Django models, views, and serializers
• Setting up testing infrastructure for Django projects

TDD Workflow for Django

Red-Green-Refactor Cycle

# Step 1: RED - Write failing test
def test_user_creation():
    user = User.objects.create_user(email='[e-mail]', password='testpass123')
    assert user.email == '[e-mail]'
    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

Setup

pytest Configuration

# 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

Test Settings

# 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 = 'django.core.mail.backends.console.EmailBackend'

# Celery always eager
CELERY_TASK_ALWAYS_EAGER = True
CELERY_TASK_EAGER_PROPAGATES = True

conftest.py

# tests/conftest.py
import pytest
from django.contrib.auth import get_user_model

User = get_user_model()

@pytest.fixture
def user(db):
    """Create a test user."""
    return User.objects.create_user(
        email='[e-mail]', password='testpass123', username='testuser'
    )

@pytest.fixture
def admin_user(db):
    """Create an admin user."""
    return User.objects.create_superuser(
        email='[e-mail]', 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

Factory Boy

Factory Setup

# tests/factories.py
import factory
from factory import fuzzy
from django.contrib.auth import get_user_model
from apps.products.models import Product, Category

User = get_user_model()

class UserFactory(factory.django.DjangoModelFactory):
    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):
    class Meta:
        model = Category

    name = factory.Faker('word')
    slug = factory.LazyAttribute(lambda obj: obj.name.lower())

class ProductFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = Product

    name = factory.Faker('sentence', nb_words=3)
    slug = factory.LazyAttribute(lambda obj: obj.name.lower().replace(' ', '-'))
    price = fuzzy.FuzzyDecimal(10.00, 1000.00, 2)
    stock = fuzzy.FuzzyInteger(, )
    is_active = 
    category = factory.SubFactory(CategoryFactory)
    created_by = factory.SubFactory(UserFactory)


     ():
          create:
            
         extracted:
             tag  extracted:
                .tags.add(tag)

Using Factories

def test_product_creation():
    product = ProductFactory(price=100.00, stock=50)
    assert product.price == 100.00
    assert product.stock == 50

def test_multiple_products():
    products = ProductFactory.create_batch(10)
    assert len(products) == 10

Test Templates

For detailed test templates covering models, views, DRF APIs, mocking, and integration testing, see test-templates.md.

Covers:

• Model tests (creation, validation, managers, string representation)
• View tests (list, detail, create, authentication checks)
• DRF serializer tests (serialization, deserialization, validation)
• DRF API viewset tests (CRUD, filtering, searching, permissions)
• Mocking external services (Stripe, email)
• Integration tests (full checkout flow)

Testing Best Practices

DO

• Use factories: Instead of manual object creation
• One assertion per test: Keep tests focused
• Descriptive test names: test_user_cannot_delete_others_post
• Test edge cases: Empty inputs, None values, boundary conditions
• Mock external services: Don't depend on external APIs
• Use fixtures: Eliminate duplication
• Test permissions: Ensure authorization works
• Keep tests fast: Use --reuse-db and --nomigrations

DON'T

• Don't test Django internals: Trust Django to work
• Don't test third-party code: Trust libraries to work
• Don't ignore failing tests: All tests must pass
• Don't make tests dependent: Tests should run in any order
• Don't over-mock: Mock only external dependencies
• Don't test private methods: Test public interface
• Don't use production database: Always use test database

Coverage

Coverage Configuration

# Run tests with coverage
pytest --cov=apps --cov-report=html --cov-report=term-missing

# Generate HTML report
open htmlcov/index.html

Coverage Goals

Component	Target Coverage
Models	90%+
Serializers	85%+
Views	80%+
Services	90%+
Utilities	80%+
Overall	80%+

Quick Reference

Pattern	Usage
@pytest.mark.django_db	Enable database access
client	Django test client
api_client	DRF API client
factory.create_batch(n)	Create multiple objects
patch('module.function')	Mock external dependencies
override_settings	Temporarily change settings
force_authenticate()	Bypass authentication in tests
assertRedirects	Check for redirects
assertTemplateUsed	Verify template usage
mail.outbox	Check sent emails

Remember: Tests are documentation. Good tests explain how your code should work. Keep them simple, readable, and maintainable.

Reference Files

• test-templates.md -- Complete test templates for models, views, DRF APIs, mocking, and integration testing