Async fixtures may break current event loop

[MarkusSintonen]

It seems pytest-asyncio (0.23.7) is currently badly broken with code relying on aiohttp.

This simple example currently breaks. The example is heavily simplified from the actual fixture setup. This used to work fine before 0.22.

import aiohttp
import pytest


# No longer working for getting a single event loop for aiohttp
# @pytest.fixture(scope="session")
# def event_loop():
#    loop = asyncio.get_event_loop_policy().new_event_loop()
#    try:
#        yield loop
#    finally:
#        loop.close()


@pytest.fixture(scope="session")
async def client(
    # event_loop <- accessing this no longer working. But neither this works without it
):
    async with aiohttp.ClientSession(
        # loop=event_loop <- aiohttp requires using a single event_loop that can not be closed between the tests...
    ) as session:
        yield session


async def test_the_client(client: aiohttp.ClientSession):
    await client.get("http://localhost:8080/foobar")  # RuntimeError: Timeout context manager should be used inside a task

Using asyncio_mode = "auto":

[tool.poetry]
name = "foobar"
package-mode = false

[tool.poetry.dependencies]
python = "~3.12"
aiohttp = "==3.9.5"

[tool.poetry.dev-dependencies]
pytest = "==8.2.2"
pytest-asyncio = "==0.23.7"

[tool.pytest.ini_options]
asyncio_mode = "auto"