django-tdd

使用 TDD 進行 Django 測試

使用 pytest、factory_boy 與 Django REST Framework 為 Django 應用程式進行測試驅動開發（Test-Driven Development）。

何時啟用

• 開發新的 Django 應用程式時
• 實作 Django REST Framework API 時
• 測試 Django 的 Model、View 與 Serializer 時
• 為 Django 專案建立測試基礎架構時

Django 的 TDD 工作流程

紅燈-綠燈-重構循環

# 步驟 1：紅燈 (RED) - 撰寫會失敗的測試
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

# 步驟 2：綠燈 (GREEN) - 讓測試通過
# 建立 User 模型或 Factory

# 步驟 3：重構 (REFACTOR) - 在保持測試通過的前提下改善程式碼

環境設定

pytest 設定

# 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

測試設定檔

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

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

# 停用 Data Migration 以提升速度
class DisableMigrations:
    def __contains__(self, item):
        return True

    def __getitem__(self, item):
        return None

MIGRATION_MODULES = DisableMigrations()

# 使用更快的密碼雜湊演算法
PASSWORD_HASHERS = [
    'django.contrib.auth.hashers.MD5PasswordHasher',
]

# Email 後端設定
EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'

# Celery 設為同步立即執行
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):
    """確保時區設定一致。"""
    settings.TIME_ZONE = 'UTC'

@pytest.fixture
def user(db):
    """建立測試用使用者。"""
    return User.objects.create_user(
        email='test@example.com',
        password='testpass123',
        username='testuser'
    )

@pytest.fixture
def admin_user(db):
    """建立管理者使用者。"""
    return User.objects.create_superuser(
        email='admin@example.com',
        password='adminpass123',
        username='admin'
    )

@pytest.fixture
def authenticated_client(client, user):
    """回傳已通過驗證的 Client。"""
    client.force_login(user)
    return client

@pytest.fixture
def api_client():
    """回傳 DRF API Client。"""
    from rest_framework.test import APIClient
    return APIClient()

@pytest.fixture
def authenticated_api_client(api_client, user):
    """回傳已通過驗證的 API Client。"""
    api_client.force_authenticate(user=user)
    return api_client

Factory Boy

Factory 設定

# 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):
    """User 模型的 Factory。"""

    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):
    """Category 模型的 Factory。"""

    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):
    """Product 模型的 Factory。"""

    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):
        """為產品新增標籤。"""
        if not create:
            return
        if extracted:
            for tag in extracted:
                self.tags.add(tag)

使用 Factory

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

def test_product_creation():
    """測試使用 Factory 建立產品。"""
    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():
    """測試帶有標籤的產品。"""
    tags = [TagFactory(name='electronics'), TagFactory(name='new')]
    product = ProductFactory(tags=tags)
    assert product.tags.count() == 2

def test_multiple_products():
    """測試一次建立多個產品。"""
    products = ProductFactory.create_batch(10)
    assert len(products) == 10

Model 測試

Model 測試項目

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

class TestUserModel:
    """測試 User 模型。"""

    def test_create_user(self, db):
        """測試建立一般使用者。"""
        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):
        """測試建立超級使用者。"""
        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):
        """測試使用者的字串表示法。"""
        user = UserFactory(email='test@example.com')
        assert str(user) == 'test@example.com'

class TestProductModel:
    """測試 Product 模型。"""

    def test_product_creation(self, db):
        """測試建立產品。"""
        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):
        """測試自動生成 Slug。"""
        product = ProductFactory(name='Test Product')
        assert product.slug == 'test-product'

    def test_product_price_validation(self, db):
        """測試價格不能為負數。"""
        product = ProductFactory(price=-10)
        with pytest.raises(ValidationError):
            product.full_clean()

    def test_product_manager_active(self, db):
        """測試 Manager 的 active 方法。"""
        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):
        """測試庫存管理。"""
        product = ProductFactory(stock=10)
        product.reduce_stock(5)
        product.refresh_from_db()
        assert product.stock == 5

        with pytest.raises(ValueError):
            product.reduce_stock(10)  # 庫存不足

View 測試

Django View 測試項目

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

class TestProductViews:
    """測試產品 View。"""

    def test_product_list(self, client, db):
        """測試產品列表 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):
        """測試產品詳細資訊 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):
        """測試建立產品需先通過身份驗證。"""
        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):
        """測試已登入使用者建立產品。"""
        response = authenticated_client.get(reverse('products:create'))

        assert response.status_code == 200

    def test_product_create_post(self, authenticated_client, db, category):
        """測試透過 POST 請求建立產品。"""
        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 測試

Serializer 測試項目

# 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:
    """測試 ProductSerializer。"""

    def test_serialize_product(self, db):
        """測試序列化產品資料。"""
        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):
        """測試反序列化產品資料。"""
        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):
        """測試價格驗證機制。"""
        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):
        """測試庫存不能為負數。"""
        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 測試項目

# 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

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