pytest-fixture学习笔记

The purpose of test fixtures is to provide a fixed baseline upon which tests can reliably and repeatedly execute. pytest fixtures offer dramatic improvements over the classic xUnit style of setup/teardown functions:

fixtures have explicit names and are activated by declaring their use from test functions, modules, classes or whole projects. fixtures are implemented in a modular manner, as each fixture name triggers a fixture function which can itself use other fixtures. fixture management scales from simple unit to complex functional testing, allowing to parametrize fixtures and tests according to configuration and component options, or to re-use fixtures across class, module or whole test session scopes.

注: 测试夹具目的是提供一个固定的装置能够可靠地重复地执行.pytest的测试夹具提供不同的方法去实现 Xunit风格的启动和关闭(setup/teardown).

夹具有明确的名字,能够通过声明在函数,模块,整个项目中使用激活. 2.
夹具管理模式能够使用不同配置和选项从而在简单,复杂的函数进行测试.

功能分析

pytest.fixture参数

scope > module, session ,function

+ module 指在每一次模块中执行一次
+ session 指在会话中执行一次
+ function 指在每个函数中执行一次

params > 类型列表,每一个是一次参数.

装饰后的fixture函数的request参数 request
- params 显而易见是参数
- addfinalizer 结束时执行
@pytest.mark.usefixtures(fixturename) 标注class使用什么fixture

import os
import pytest

@pytest.mark.usefixtures("cleandir")
class TestDirectoryInit:
    def test_cwd_starts_empty(self):
        assert os.listdir(os.getcwd()) == []
        with open("myfile", "w") as f:
            f.write("hello")

    def test_cwd_again_starts_empty(self):
        assert os.listdir(os.getcwd()) == []

配置文件

# content of pytest.ini
[pytest]
usefixtures = cleandir # 每个模块都会执行一次!

fixture 的一个库factory_boy

As a fixtures replacement tool, it aims to replace static, hard to maintain fixtures with easy-to-use factories for complex object.

目标是代替静态,难于维护的fixture,从而对于复杂的对象容易使用.

测试代码目录

demo/2015-12-14/pytest-fixture