测试

Flask 提供了测试客户端和与 pytest 的集成，方便进行单元测试和集成测试。

安装

pip install pytest pytest-flask coverage

测试配置

# config.py
class Config:
    SECRET_KEY = 'dev-key'
    SQLALCHEMY_DATABASE_URI = 'sqlite:///app.db'

class TestConfig(Config):
    TESTING = True
    SQLALCHEMY_DATABASE_URI = 'sqlite:///:memory:'
    WTF_CSRF_ENABLED = False

测试固件

# tests/conftest.py
import pytest
from app import create_app
from app.extensions import db
from config import TestConfig

@pytest.fixture
def app():
    app = create_app(TestConfig)
    
    with app.app_context():
        db.create_all()
        yield app
        db.drop_all()

@pytest.fixture
def client(app):
    return app.test_client()

@pytest.fixture
def runner(app):
    return app.test_cli_runner()

基本测试

测试路由

# tests/test_routes.py
def test_index(client):
    response = client.get('/')
    assert response.status_code == 200
    assert b'Hello' in response.data

def test_404(client):
    response = client.get('/nonexistent')
    assert response.status_code == 404

测试表单

def test_login_success(client):
    response = client.post('/auth/login', data={
        'username': 'testuser',
        'password': 'testpass'
    }, follow_redirects=True)
    
    assert response.status_code == 200
    assert b'登录成功' in response.data

def test_login_failure(client):
    response = client.post('/auth/login', data={
        'username': 'wrong',
        'password': 'wrong'
    })
    
    assert b'用户名或密码错误' in response.data

数据库测试

# tests/test_models.py
from app.models.user import User

def test_user_creation(app):
    with app.app_context():
        user = User(username='test', email='[email protected]')
        user.set_password('password')
        db.session.add(user)
        db.session.commit()
        
        assert user.id is not None
        assert user.check_password('password')
        assert not user.check_password('wrong')

def test_user_unique_constraint(app):
    with app.app_context():
        user1 = User(username='test', email='[email protected]')
        user2 = User(username='test', email='[email protected]')
        
        db.session.add(user1)
        db.session.commit()
        
        db.session.add(user2)
        with pytest.raises(Exception):
            db.session.commit()

认证测试

# tests/test_auth.py
import pytest
from flask_login import current_user

def test_login_required(client):
    response = client.get('/dashboard', follow_redirects=True)
    assert b'请先登录' in response.data

class TestAuth:
    @pytest.fixture(autouse=True)
    def setup_user(self, app):
        with app.app_context():
            user = User(username='test', email='[email protected]')
            user.set_password('testpass')
            db.session.add(user)
            db.session.commit()
            self.user_id = user.id
    
    def test_login(self, client):
        response = client.post('/auth/login', data={
            'username': 'test',
            'password': 'testpass'
        }, follow_redirects=True)
        
        assert response.status_code == 200
    
    def test_logout(self, client):
        # 先登录
        client.post('/auth/login', data={
            'username': 'test',
            'password': 'testpass'
        })
        
        # 再登出
        response = client.get('/auth/logout', follow_redirects=True)
        assert b'已退出登录' in response.data

API 测试

# tests/test_api.py
import json

def test_get_users(client):
    response = client.get('/api/v1/users')
    assert response.status_code == 200
    data = json.loads(response.data)
    assert isinstance(data, list)

def test_create_user(client):
    response = client.post('/api/v1/users',
        data=json.dumps({
            'username': 'newuser',
            'email': '[email protected]',
            'password': 'newpass'
        }),
        content_type='application/json'
    )
    
    assert response.status_code == 201
    data = json.loads(response.data)
    assert data['username'] == 'newuser'

def test_update_user(client, app):
    with app.app_context():
        user = User.query.first()
        
        response = client.put(f'/api/v1/users/{user.id}',
            data=json.dumps({'username': 'updated'}),
            content_type='application/json'
        )
        
        assert response.status_code == 200
        data = json.loads(response.data)
        assert data['username'] == 'updated'

使用 Test Client

def test_with_session(client):
    with client.session_transaction() as sess:
        sess['user_id'] = 1
    
    response = client.get('/profile')
    assert response.status_code == 200

def test_file_upload(client):
    data = {
        'file': (io.BytesIO(b'my file contents'), 'test.txt')
    }
    response = client.post('/upload', data=data, content_type='multipart/form-data')
    assert response.status_code == 200

覆盖率测试

# 运行测试并生成覆盖率报告
pytest --cov=app --cov-report=html

# 查看终端报告
pytest --cov=app --cov-report=term-missing

测试组织

tests/
├── conftest.py
├── test_auth.py
├── test_models.py
├── test_routes.py
├── test_api.py
└── test_forms.py

测试最佳实践

1. 每个测试独立: 测试之间不应相互依赖
2. 使用固件: 复用测试数据和配置
3. 测试边界情况: 空值、最大值、异常输入
4. 保持测试快速: 使用内存数据库
5. 命名清晰: 测试函数名描述测试内容

下一步

学习如何部署 Flask 应用到生产环境。