Conflicts with pytest-asyncio (sample with redis)

[vlcinsky]

Having following test file, things behave differently with different pytest plugins installed:

import aioredis
import pytest
from aiohttp import web

def init():
    """Create web.Application instance
    """
    app = web.Application()
    app.router.add_get('/', hello)
    app["redis_url"] = "redis://localhost:6379"
    app.on_startup.append(create_redis_pool)
    app.on_shutdown.insert(0, close_redis_pool)
    return app

async def hello(request):
    """url Handler for hello"""
    return web.Response(text='Hello, world')

async def create_redis_pool(app):
    """Create Redis connection pool"""
    redis_url = app["redis_url"]
    pool = await aioredis.create_redis_pool(redis_url, loop=app.loop)
    app["redis_pool"] = pool

async def close_redis_pool(app):
    """Close Redis connection pool"""
    pool = app["redis_pool"]
    pool.close()
    await pool.wait_closed()

# @pytest.fixture
# def loop(event_loop):
#     """Ensure usable event loop for everyone.
#
#     If you comment this fixture out, default pytest-aiohttp one is used
#     and things start failing (when redis pool is in place).
#     """
#     return event_loop

@pytest.fixture
def app(loop):
    """Application instance.
    """
    return init()

@pytest.fixture
async def cli(test_client, app, loop):
    """HTTP client for our application.
    """
    return await test_client(app)

async def test_hello(cli, loop):
    resp = await cli.get("/")
    assert resp.status == 200
    text = await resp.text()
    assert "Hello, world" in text

only pytest-aiohttp installed: all is fine

When only pytest-aiohttp is installed, the test runs well as it is.

============================================================================================= test session starts =============================================================================================
platform linux -- Python 3.6.3, pytest-3.4.0, py-1.5.2, pluggy-0.6.0
rootdir: /home/javl/devel/tis/dpo-tis-pns, inifile:
collected 1 item

tests/http/test_redisloop.py .                                                                                                                                                                          [100%]

========================================================================================== 1 passed in 0.06 seconds ===========================================================================================

[Process exited 0]

with pytest-asyncio, it fails

When also pytest-asyncio is installed, the test fails with:

self = <ConnectionsPool [db:0, size:[1:10], free:0]>

    async def wait_closed(self):
        """Wait until pool gets closed."""
        await self._close_state.wait()
        assert self._close_waiter is not None
>       await asyncio.shield(self._close_waiter, loop=self._loop)
E       RuntimeError: Task <Task pending coro=<pytest_fixture_setup.<locals>.wrapper.<locals>.setup() running at /home/javl/devel/tis/dpo-tis-pns/.tox/py36/lib/python3.6/site-packages/pytest_asyncio/plugin.p
y:117> cb=[_run_until_complete_cb() at /home/javl/.pyenv/versions/3.6.3/lib/python3.6/asyncio/base_events.py:176]> got Future <Future pending> attached to a different loop

.tox/py36/lib/python3.6/site-packages/aioredis/pool.py:177: RuntimeError
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> entering PDB >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
[33] > /home/javl/devel/tis/dpo-tis-pns/.tox/py36/lib/python3.6/site-packages/aioredis/pool.py(177)wait_closed()
-> await asyncio.shield(self._close_waiter, loop=self._loop)
   6 frames hidden (try 'help hidden_frames')
(Pdb++)

fix by masking loop fixture

To fix this problem (still using pytest-asyncio plugin), one has to uncomment the loop fixture.

[vlcinsky]

See also https://github.com/pytest-dev/pytest-asyncio/issues/76

[asvetlov]

I see no pool fixture in your code

[vlcinsky]

@asvetlov thanks for heads up, I meant loop (not pool). I fixed the description.

[scottbelden]

This has also caused me some headaches as well when trying to write tests and having both pytest-aiohttp and pytest-asyncio installed. So far I've been the most successful with redefining the loop fixture to use the event_loop fixture as mentioned here.

[gjcarneiro]

me too;

At least it seems like I can reasonably get away with using only pytest-aiohttp and just skip pytest-asyncio entirely. So not that big a problem. Just time wasting and confusing for developers.

[scottbelden]

While it's nice that many people can get away with only using the pytest-aiohttp plugin, I don't think this is always possible. I can double check if necessary, but I remember a case where I couldn't just use the aiohttp plugin. I think it was a test that didn't use any aiohttp fixtures and was just a simple async test and got some exception.

Sorry for the worst description ever, but if it would be useful I can try to reproduce what I was seeing.

[ChristopheLallement]

I think I've encouter same issue with a shorted code using ThreadPoolExecutor without redis. It seems that I can't use loop fixture from pytest-aiohttp while pytest-asyncio > 0.5.0 is installed.

Following source using event_loopfixture from pytest-asyncio is working fine with pytest-asyncio == 0.8.0 installed :

import asyncio
import pytest
from concurrent.futures import ThreadPoolExecutor

def count():
    return  0

@pytest.fixture
async def my_fixture(event_loop):
    executor = ThreadPoolExecutor()    
    await event_loop.run_in_executor(executor, count)

async def test_f(my_fixture):
    pass

Following source with loop fixture from pytest-aiohttp :

• is working fine if pytest-asyncio is not installed
• also working fine if pytest-asyncio == 0.5.0 is installed
• doesn't work if pytest-asyncio == 0.8.0 is installed

import asyncio
import pytest
from concurrent.futures import ThreadPoolExecutor

def count():
    return  0

@pytest.fixture
async def my_fixture(loop):
    executor = ThreadPoolExecutor()    
    await loop.run_in_executor(executor, count)

async def test_f(my_fixture):
    pass

[asvetlov]

pytest-asyncio and pytest-aiohttp libraries are not compatible. That's sad but we should live with it.