如何在pytest fixture中yield Playwright对象复用？遇执行异常

核心问题：未正确使用Fixture #

你定义了playwright_instance fixture，但测试函数test_for_SObject_connectivity完全没用到它——你在测试代码里重新用async with async_playwright()创建了实例，和fixture毫无关联。先把测试代码修正为正确使用fixture的形式：

import asyncio, pytest
from SingletonObject import SObject
from playwright.async_api import expect, async_playwright

@pytest.fixture
async def playwright_instance():
    async with async_playwright() as playwright:
        yield playwright

# 将fixture作为参数传入，pytest会自动注入实例
async def test_for_SObject_connectivity(playwright_instance):
    # 移除测试内的async with async_playwright()，直接使用fixture注入的实例
    test = SObject(playwright_instance) 
    await test.start() 
    await expect(test.search_page).to_have_url("[specific url]")

异步Fixture的必要配置 #

使用异步fixture必须确保pytest-asyncio正确配置：

• 确保已安装pytest-asyncio
• 在项目根目录创建pytest.ini文件，添加以下内容避免事件循环冲突：

[pytest]
asyncio_mode = auto

关于Playwright官方插件的问题 #

使用官方插件时出现RuntimeError: Cannot run the event loop while another loops is running，通常原因是：

• 自定义fixture与插件提供的fixture重复创建事件循环
• 插件已封装playwright、browser、page等fixture，无需自行定义playwright_instance

若要使用官方插件，直接调用其提供的fixture即可，示例：

import pytest
from SingletonObject import SObject
from playwright.async_api import expect

# 直接使用插件的playwright fixture
async def test_for_SObject_connectivity(playwright):
    test = SObject(playwright) 
    await test.start() 
    await expect(test.search_page).to_have_url("[specific url]")

同时保证pytest.ini的asyncio_mode配置正确，不要同时运行自定义异步fixture和插件fixture，避免循环冲突。

总结 #

1. 修正测试函数，正确传入fixture参数，不要在测试内重复创建Playwright实例
2. 配置pytest-asyncio的异步模式，解决事件循环冲突问题
3. 使用官方插件时，直接调用其提供的fixture，避免重复定义引发的问题

内容的提问来源于stack exchange，提问作者Cameron Wetzel