django-tdd

Django Testing with TDD (TDD 기반 Django 테스트)

pytest, factory_boy 및 Django REST Framework를 사용한 Django 애플리케이션의 테스트 주도 개발.

활성화 시점

• 새로운 Django 애플리케이션 작성 중
• Django REST Framework API 구현 중
• Django 모델, 뷰, 시리얼라이저 테스트 중
• Django 프로젝트 테스트 인프라 설정 중

TDD Workflow for Django (Django용 TDD 워크플로우)

Red-Green-Refactor Cycle (Red-Green-Refactor 사이클)

# Step 1: RED - Write failing test
# 1단계: RED - 실패하는 테스트 작성
def test_user_creation():
    user = User.objects.create_user(email='[email protected]', password='testpass123')
    assert user.email == '[email protected]'
    assert user.check_password('testpass123')
    assert not user.is_staff

# Step 2: GREEN - Make test pass
# 2단계: GREEN - 테스트 통과시키기
# User 모델 또는 팩토리 생성

# Step 3: REFACTOR - Improve while keeping tests green
# 3단계: REFACTOR - 테스트를 유지하면서 개선

Setup (설정)

pytest Configuration (pytest 설정)

# 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 (느린 테스트 표시)
    integration: marks tests as integration tests (통합 테스트 표시)

Test Settings (테스트 설정)

# config/settings/test.py
from .base import *

DEBUG = True
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': ':memory:',
    }
}

# Disable migrations for speed (속도 향상을 위해 마이그레이션 비활성화)
class DisableMigrations:
    def __contains__(self, item):
        return True

    def __getitem__(self, item):
        return None

MIGRATION_MODULES = DisableMigrations()

# Faster password hashing (더 빠른 비밀번호 해싱)
PASSWORD_HASHERS = [
    'django.contrib.auth.hashers.MD5PasswordHasher',
]

# Email backend (이메일 백엔드)
EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'

# Celery always eager (Celery 항상 즉시 실행)
CELERY_TASK_ALWAYS_EAGER = True
CELERY_TASK_EAGER_PROPAGATES = True

conftest.py

# 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. (일관된 시간대 보장)"""
    settings.TIME_ZONE = 'UTC'

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

@pytest.fixture
def admin_user(db):
    """Create an admin user. (관리자 사용자 생성)"""
    return User.objects.create_superuser(
        email='[email protected]',
        password='adminpass123',
        username='admin'
    )

@pytest.fixture
def authenticated_client(client, user):
    """Return authenticated client. (인증된 클라이언트 반환)"""
    client.force_login(user)
    return client

@pytest.fixture
def api_client():
    """Return DRF API client. (DRF API 클라이언트 반환)"""
    from rest_framework.test import APIClient
    return APIClient()

@pytest.fixture
def authenticated_api_client(api_client, user):
    """Return authenticated API client. (인증된 API 클라이언트 반환)"""
    api_client.force_authenticate(user=user)
    return api_client

Factory Boy

Factory Setup (팩토리 설정)

# 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. (User 모델 팩토리)"""

    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. (Category 모델 팩토리)"""

    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. (Product 모델 팩토리)"""

    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. (제품에 태그 추가)"""
        if not create:
            return
        if extracted:
            for tag in extracted:
                self.tags.add(tag)

Using Factories (팩토리 사용)

# tests/test_models.py
import pytest
from tests.factories import ProductFactory, UserFactory

def test_product_creation():
    """Test product creation using factory. (팩토리를 사용한 제품 생성 테스트)"""
    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. (태그가 있는 제품 테스트)"""
    tags = [TagFactory(name='electronics'), TagFactory(name='new')]
    product = ProductFactory(tags=tags)
    assert product.tags.count() == 2

def test_multiple_products():
    """Test creating multiple products. (여러 제품 생성 테스트)"""
    products = ProductFactory.create_batch(10)
    assert len(products) == 10

Model Testing (모델 테스트)

Model Tests (모델 테스트)

# tests/test_models.py
import pytest
from django.core.exceptions import ValidationError
from tests.factories import UserFactory, ProductFactory

class TestUserModel:
    """Test User model. (User 모델 테스트)"""

    def test_create_user(self, db):
        """Test creating a regular user. (일반 사용자 생성 테스트)"""
        user = UserFactory(email='[email protected]')
        assert user.email == '[email protected]'
        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. (슈퍼유저 생성 테스트)"""
        user = UserFactory(
            email='[email protected]',
            is_staff=True,
            is_superuser=True
        )
        assert user.is_staff
        assert user.is_superuser

    def test_user_str(self, db):
        """Test user string representation. (사용자 문자열 표현 테스트)"""
        user = UserFactory(email='[email protected]')
        assert str(user) == '[email protected]'

class TestProductModel:
    """Test Product model. (Product 모델 테스트)"""

    def test_product_creation(self, db):
        """Test creating a product. (제품 생성 테스트)"""
        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. (자동 slug 생성 테스트)"""
        product = ProductFactory(name='Test Product')
        assert product.slug == 'test-product'

    def test_product_price_validation(self, db):
        """Test price cannot be negative. (가격이 음수일 수 없음 테스트)"""
        product = ProductFactory(price=-10)
        with pytest.raises(ValidationError):
            product.full_clean()

    def test_product_manager_active(self, db):
        """Test active manager method. (활성 매니저 메서드 테스트)"""
        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. (재고 관리 테스트)"""
        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 (재고 부족)

View Testing (뷰 테스트)

Django View Testing (Django 뷰 테스트)

# tests/test_views.py
import pytest
from django.urls import reverse
from tests.factories import ProductFactory, UserFactory

class TestProductViews:
    """Test product views. (제품 뷰 테스트)"""

    def test_product_list(self, client, db):
        """Test product list view. (제품 목록 뷰 테스트)"""
        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. (제품 상세 뷰 테스트)"""
        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. (제품 생성 시 인증 필요 테스트)"""
        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. (인증된 사용자로 제품 생성 테스트)"""
        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. (POST로 제품 생성 테스트)"""
        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()

DRF API Testing (DRF API 테스트)

Serializer Testing (시리얼라이저 테스트)

# 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. (ProductSerializer 테스트)"""

    def test_serialize_product(self, db):
        """Test serializing a product. (제품 직렬화 테스트)"""
        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. (제품 데이터 역직렬화 테스트)"""
        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. (가격 검증 테스트)"""
        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. (재고가 음수일 수 없음 테스트)"""
        data = {
            'name': 'Test Product',
            'price': '99.99',
            'stock': -5,
        }

        serializer = ProductSerializer(data=data)

        assert not serializer.is_valid()
        assert 'stock' in serializer.errors

API ViewSet Testing (API ViewSet 테스트)

# 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. (Product API 엔드포인트 테스트)"""

    @pytest.fixture
    def api_client(self):
        """Return API client. (API 클라이언트 반환)"""
        return APIClient()

    def test_list_products(self, api_client, db):
        """Test listing products. (제품 목록 조회 테스트)"""
        ProductFactory.create_batch(10)

        url = reverse('api:product-list')
        response = api_client.get(url)

        assert response.status_code == status.HTTP_200_OK
        assert response.data['count'] == 10

    def test_retrieve_product(self, api_client, db):
        """Test retrieving a product. (제품 조회 테스트)"""
        product = ProductFactory()

        url = reverse('api:product-detail', kwargs={'pk': product.id})
        response = api_client.get(url)

        assert response.status_code == status.HTTP_200_OK
        assert response.data['id'] == product.id

    def test_create_product_unauthorized(self, api_client, db):
        """Test creating product without authentication. (인증 없이 제품 생성 테스트)"""
        url = reverse('api:product-list')
        data = {'name': 'Test Product', 'price': '99.99'}

        response = api_client.post(url, data)

        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_create_product_authorized(self, authenticated_api_client, db):
        """Test creating product as authenticated user. (인증된 사용자로 제품 생성 테스트)"""
        url = reverse('api:product-list')
        data = {
            'name': 'Test Product',
            'description': 'Test',
            'price': '99.99',
            'stock': 10,
        }

        response = authenticated_api_client.post(url, data)

        assert response.status_code == status.HTTP_201_CREATED
        assert response.data['name'] == 'Test Product'

    def test_update_product(self, authenticated_api_client, db):
        """Test updating a product. (제품 업데이트 테스트)"""
        product = ProductFactory(created_by=authenticated_api_client.user)

        url = reverse('api:product-detail', kwargs={'pk': product.id})
        data = {'name': 'Updated Product'}

        response = authenticated_api_client.patch(url, data)

        assert response.status_code == status.HTTP_200_OK
        assert response.data['name'] == 'Updated Product'

    def test_delete_product(self, authenticated_api_client, db):
        """Test deleting a product. (제품 삭제 테스트)"""
        product = ProductFactory(created_by=authenticated_api_client.user)

        url = reverse('api:product-detail', kwargs={'pk': product.id})

        response = authenticated_api_client.delete(url)

        assert response.status_code == status.HTTP_204_NO_CONTENT
        assert not Product.objects.filter(id=product.id).exists()