# RuntimeError: 没有正在运行的事件循环
async def 函数未被原生支持。你需要为异步框架安装合适的插件，例如：- anyio - pytest-asyncio

- **ID:** `python/pytest-asyncio-no-event-loop`
- **领域:** python
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

pytest 在没有插件的情况下不会运行异步测试函数；未配置 pytest-asyncio（或 anyio）时，协程测试被跳过或抛出此错误。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 7.x | active | — | — |
| 8.x | active | — | — |

## 解决方案

1. **** (95% 成功率)
   ```
   pip install pytest-asyncio

# pytest.ini
[pytest]
asyncio_mode = auto

# tests
import pytest

@pytest.mark.asyncio
async def test_fetch():
    assert await fetch()
   ```
2. **** (90% 成功率)
   ```
   pip install anyio

# pytest.ini
[pytest]
addopts = --anyio-mode=auto

# tests
import pytest

@pytest.mark.anyio
async def test_fetch():
    assert await fetch()
   ```

## 无效尝试

- **** — Works for trivial tests but breaks fixtures, event-loop-scoped resources, and any test that relies on pytest's async fixtures. (60% 失败率)
- **** — The marker is unknown to pytest and triggers a PytestUnknownMarkWarning; the coroutine is still not awaited. (90% 失败率)
- **** — The ini option is only recognized by pytest-asyncio; without the plugin it has no effect. (95% 失败率)