ScopeMismatch error when adding fixture as parameter

[ddsl]

I got a ScopeMismatch error when tried to add fixture to my test fucntion in a class when I add the scope parameter (scope='class' or scope='module'):
My case:

import asyncio
import pytest
import pytest_asyncio
from .database import DB

@pytest.fixture(scope='class')
async def db_setup(request):
    print("\nconnect to db")
    db = await DB.create()
    async def resource_teardown():
        await db.close()
        print("\ndisconnect")
    request.addfinalizer(resource_teardown)
    return db


class TestDB:
    @pytest.mark.asyncio
    async def test_connection(self, event_loop, db_setup):
        db = await db_setup
        with await db._pool as redis:
            res = await redis.ping()
            print(res)
            assert res, "PONG"

And when i run it i get :

 ScopeMismatch: You tried to access the 'function' scoped fixture 'event_loop' with a 'class' scoped request object, involved factories
../../../../../.virtualenvs/jwt_auth/lib/python3.5/site-packages/pytest_asyncio/plugin.py:110:  def wrapper(*args, **kwargs)


==================================== ERRORS ====================================
___________________ ERROR at setup of TestDB.test_connection ___________________
ScopeMismatch: You tried to access the 'function' scoped fixture 'event_loop' with a 'class' scoped request object, involved factories
../../../../../.virtualenvs/jwt_auth/lib/python3.5/site-packages/pytest_asyncio/plugin.py:110:  def wrapper(*args, **kwargs)
============================== 5 tests deselected ==============================
==================== 5 deselected, 1 error in 0.17 seconds =====================

Process finished with exit code 0

I tried to delete the event_loop param but it gave the same error but when i removed scope parameter from the fixture everithing works

[Tinche]

Hello,

unfortunately you always need the event_loop fixture, even if you don't ask for it explicitely (because you need it to run your test and fixtures).

From the docs (a little buried I admit): All scopes are supported, but if you use a non-function scope you will need to redefine the event_loop fixture to have the same or broader scope. Async fixtures need the event loop, and so must have the same or narrower scope than the event_loop fixture.

Try redefining the event_loop fixture like this:

@pytest.yield_fixture(scope='class')
def event_loop(request):
    loop = asyncio.get_event_loop_policy().new_event_loop()
    yield loop
    loop.close()

[ddsl]

Thanks for answer!
I did as you say and got another:

request = <SubRequest 'db_setup' for <Function 'test_connection'>>

    @pytest.fixture(scope='class')
    async def db_setup(request):
        print("\nconnect to db")
>       db = await DB.create()

test_database.py:16: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../jwt_auth_service/database.py:15: in create
    encoding='utf-8')
/home/pel/.virtualenvs/jwt_auth/lib/python3.5/site-packages/aioredis/pool.py:49: in create_pool
    yield from pool.wait_closed()
/home/pel/.virtualenvs/jwt_auth/lib/python3.5/site-packages/aioredis/pool.py:154: in wait_closed
    yield from asyncio.shield(self._close_waiter, loop=self._loop)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <Future pending>

    def __iter__(self):
        if not self.done():
            self._blocking = True
>           yield self  # This tells Task to wait for completion.
E           RuntimeError: Task <Task pending coro=<pytest_fixture_setup.<locals>.wrapper.<locals>.setup() running at /home/pel/.virtualenvs/jwt_auth/lib/python3.5/site-packages/pytest_asyncio/plugin.py:117> cb=[_run_until_complete_cb() at /usr/lib/python3.5/asyncio/base_events.py:164]> got Future <Future pending> attached to a different loop

/usr/lib/python3.5/asyncio/futures.py:361: RuntimeError

But when i remove all scopes params everything works fine.

[Tinche]

Hmm.

Could you put together a small example so I can debug it? Simplest possible where the bug is visible, you can just await asyncio.sleep in the fixture.

[ddsl]

Okay, see this https://github.com/ddsl/simple-async-jwtauth

[Tinche]

Hi,

I installed your example into a clean Python 3.6 virtualenv. Didn't get the ScopeMismatch errors, but I did get some warnings with request.addfinalizer. You don't need to use it though, I fixed it up over here (https://gist.github.com/Tinche/96457dedcb34ba6653373469371a95da) and it seems to work. Is this good for you?

[ddsl]

Thank you a lot. It didn't help but i think it is indecent to take so much time from someone for the sake of trivia. most likely the problem is in me rather than your code.

[Tinche]

Alright, if you want to continue just reopen :)