pytestmark not being applied for pytest-asyncio

[Tinche]

Hi,

I'm the maintainer of pytest-asyncio.

Pytest-asyncio uses a marker, @pytest.mark.asyncio, with some optional parameters. To save typing, I was going to suggest my users use something like this:

import asyncio
import pytest

pytestmark = pytest.mark.asyncio(forbid_global_loop=True)

async def test_subprocess(event_loop):
    await asyncio.sleep(0)

instead of:

import asyncio
import pytest

@pytest.mark.asyncio(forbid_global_loop=True)
async def test_subprocess(event_loop):
    await asyncio.sleep(0)

These two should be equivalent, right? But they aren't. pytest-asyncio uses a pytest_pycollect_makeitem hook:

@pytest.mark.tryfirst
def pytest_pycollect_makeitem(collector, name, obj):
    if collector.funcnamefilter(name) and _is_coroutine(obj):
        item = pytest.Function(name, parent=collector)
        if ('asyncio' in item.keywords or
           'asyncio_process_pool' in item.keywords):
            return list(collector._genfunctions(name, obj))

but using the pytestmark approach, the 'asyncio' keyword isn't in item.keywords.

I'm not saying pytest is doing something wrong here, I'm saying help me make this work. :)

[nicoddemus]

Hi @Tinche,

My guess is that the mark propagation mechanism is not picking up async functions, so it is a bug in pytest. The code in question is in transfer_markers function, I believe.

Sorry for not being able to help out more right now.

[Tinche]

Haha, s'alright, it's not an urgent thing. Maybe I'll dig around in the pytest source too, try to see what I can find.

[Tinche]

It turned out pytest applies the module- and class-level markers after collection, so I just made pytest-asyncio do this manually when I need it to happen.