⚡

Pytest测试框架 pytest

Pytest 是一个功能强大、灵活的 Python 测试框架，用于编写和执行自动化测试。它支持单元测试、集成测试和功能测试，提供夹具、参数化、异步测试等高级功能，帮助开发者提高代码质量和开发效率。关键词：Python测试，自动化测试，单元测试，集成测试，测试框架，pytest，软件测试，测试驱动开发。

测试 0 次安装 0 次浏览 更新于 3/2/2026

name: pytest description: Python测试框架，用于编写简单、可扩展且功能强大的测试 when_to_use: 当您需要使用夹具、参数化或异步测试来编写、运行或组织Python测试时

Pytest 测试框架

Pytest 是一个成熟的 Python 测试框架，它使得编写小型测试变得容易，同时能够扩展以支持复杂的功能测试。

快速开始

基本测试结构

# test_example.py
def test_addition():
    assert 2 + 2 == 4

def test_string_operations():
    assert "hello".upper() == "HELLO"
    assert "world" in "hello world"

运行测试

# 运行所有测试
uv run pytest

# 以详细输出运行
uv run pytest -v

# 运行特定测试文件
uv run pytest test_example.py

# 运行特定测试函数
uv run pytest test_example.py::test_addition

常用模式

夹具

基本夹具定义：

import pytest

@pytest.fixture
def sample_data():
    return {"name": "Alice", "age": 30}

def test_user_data(sample_data):
    assert sample_data["name"] == "Alice"
    assert sample_data["age"] == 30

带设置和清理的夹具：

@pytest.fixture
def database_connection():
    # 设置
    conn = create_database_connection()
    yield conn
    # 清理
    conn.close()

def test_database_query(database_connection):
    result = database_connection.query("SELECT * FROM users")
    assert len(result) > 0

夹具作用域：

@pytest.fixture(scope="function")  # 默认 - 每个测试创建一次
def temp_file():
    pass

@pytest.fixture(scope="module")    # 每个模块创建一次
def module_resource():
    pass

@pytest.fixture(scope="session")   # 每个测试会话创建一次
def session_resource():
    pass

参数化

基本参数化：

@pytest.mark.parametrize("input,expected", [
    ("3+5", 8),
    ("2+4", 6),
    ("6*9", 54),
])
def test_eval(input, expected):
    assert eval(input) == expected

参数化夹具：

@pytest.fixture(params=["mysql", "postgresql", "sqlite"])
def database(request):
    if request.param == "mysql":
        return MySQLConnection()
    elif request.param == "postgresql":
        return PostgreSQLConnection()
    else:
        return SQLiteConnection()

def test_database_operations(database):
    # 测试运行3次，每种数据库类型一次
    result = database.execute("SELECT 1")
    assert result == 1

堆叠参数化进行组合测试：

@pytest.mark.parametrize("x", [0, 1])
@pytest.mark.parametrize("y", [2, 3])
def test_combinations(x, y):
    # 运行4次: (0,2), (0,3), (1,2), (1,3)
    assert x + y > 1

异步测试

基本异步测试：

import pytest

@pytest.mark.asyncio
async def test_async_function():
    result = await async_operation()
    assert result is not None

异步夹具：

@pytest.fixture
async def async_client():
    client = AsyncClient()
    await client.connect()
    yield client
    await client.disconnect()

@pytest.mark.asyncio
async def test_async_api(async_client):
    response = await async_client.get("/api/data")
    assert response.status_code == 200

测试组织

使用 conftest.py 共享夹具：

# conftest.py
@pytest.fixture
def authenticated_client():
    client = create_test_client()
    client.login("testuser", "password")
    return client

@pytest.fixture(scope="session")
def test_database():
    db = create_test_database()
    yield db
    db.cleanup()

测试类：

class TestUserAPI:
    def test_create_user(self, authenticated_client):
        response = authenticated_client.post("/users", json={"name": "John"})
        assert response.status_code == 201

    def test_get_user(self, authenticated_client):
        user_id = create_test_user()
        response = authenticated_client.get(f"/users/{user_id}")
        assert response.status_code == 200

模拟和打补丁

使用 monkeypatch 夹具：

def test_environment_variable(monkeypatch):
    monkeypatch.setenv("API_KEY", "test-key")
    assert get_api_key() == "test-key"

def test_file_operations(monkeypatch, tmp_path):
    test_file = tmp_path / "test.txt"
    test_file.write_text("test content")

    monkeypatch.setattr("module.FILE_PATH", str(test_file))
    assert read_file_content() == "test content"

标记器和选择

自定义标记器：

# pytest.ini
[tool:pytest]
markers =
    slow: 标记测试为慢速测试
    integration: 标记测试为集成测试
    unit: 标记测试为单元测试

# test_file.py
@pytest.mark.slow
def test_expensive_operation():
    pass

@pytest.mark.integration
def test_database_integration():
    pass

按标记器运行测试：

# 仅运行单元测试
uv run pytest -m unit

# 跳过慢速测试
uv run pytest -m "not slow"

# 运行集成或单元测试
uv run pytest -m "integration or unit"

实用代码片段

API 测试

import pytest
from fastapi.testclient import TestClient
from myapp import app

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

@pytest.fixture
def test_user():
    return {"username": "testuser", "email": "test@example.com"}

def test_create_user(client, test_user):
    response = client.post("/users/", json=test_user)
    assert response.status_code == 201
    assert response.json()["username"] == test_user["username"]

def test_get_user(client, test_user):
    # 首先创建用户
    create_response = client.post("/users/", json=test_user)
    user_id = create_response.json()["id"]

    # 获取用户
    response = client.get(f"/users/{user_id}")
    assert response.status_code == 200
    assert response.json()["email"] == test_user["email"]

数据库测试

import pytest
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

@pytest.fixture(scope="function")
def test_db():
    engine = create_engine("sqlite:///:memory:")
    Session = sessionmaker(bind=engine)
    Base.metadata.create_all(engine)
    session = Session()
    yield session
    session.close()

def test_user_creation(test_db):
    user = User(name="John", email="john@example.com")
    test_db.add(user)
    test_db.commit()

    retrieved_user = test_db.query(User).filter_by(name="John").first()
    assert retrieved_user.email == "john@example.com"

错误处理测试

def test_invalid_input_raises_error():
    with pytest.raises(ValueError, match="Invalid input"):
        process_input("invalid")

def test_file_not_found():
    with pytest.raises(FileNotFoundError):
        read_nonexistent_file()

def test_custom_exception():
    with pytest.raises(CustomAPIError) as exc_info:
        call_api_endpoint()
    assert exc_info.value.status_code == 404
    assert "not found" in str(exc_info.value)

要求

  • Python 3.7+
  • pytest (uv add --dev pytest)
  • 对于异步测试: pytest-asyncio (uv add --dev pytest-asyncio)
  • 对于API测试: Web框架测试客户端 (例如，uv add --dev httpx 用于异步HTTP测试)