feat: Configuration option for setting default loop_scope for tests

[Novakov]

New configuration option, asyncio_default_test_loop_scope, provides default value for loop_scope argument of asyncio marker. This can be used to use the same event loop in auto mode without need to use modifyitems hook.

Test functions can still override loop_scope by using asyncio marker.

Implements #793

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.27%. Comparing base (2188cdb) to head (6c3a941).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1035      +/-   ##
==========================================
+ Coverage   91.13%   91.27%   +0.13%     
==========================================
  Files           2        2              
  Lines         564      573       +9     
  Branches       74       75       +1     
==========================================
+ Hits          514      523       +9     
  Misses         30       30              
  Partials       20       20              

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[seifertm]

Thank you! I really like how you changed _get_marked_loop_scope and how you used functions to keep the code readable.

Can you please add an entry to docs/reference/changelog.rst where you link to #793 ?
Assume that this PR bumps the minor version and set the date to UNRELEASED.

[Novakov]

Thanks for kind words. I've rebased this branch and applied modifications you requested.

[seifertm]

Thanks!

[michaelxiacs]

Thanks!

Is this feature currently available in pytest-asyncio>=0.25.2?

I try to set asyncio_default_test_loop_scope = session in pytest.ini and it doesn't seem to work.

pytest.ini

[pytest]
addopts = -p no:cacheprovider
asyncio_mode = auto
asyncio_default_fixture_loop_scope = session
asyncio_default_test_loop_scope = session

test_demo.py

import asyncio


async def test1():
    loop_id = id(asyncio.get_running_loop())
    print(test1.__name__, loop_id)
    assert True


async def test2():
    loop_id = id(asyncio.get_running_loop())
    print(test2.__name__, loop_id)
    assert True

Here is the result when I run it

> uv run pytest -s
========================================================= test session starts ==========================================================
platform win32 -- Python 3.11.11, pytest-8.3.4, pluggy-1.5.0
rootdir: C:\Users\Abon\Documents\Code\Projects\python\dev\tests
configfile: pytest.ini
plugins: asyncio-0.25.2
asyncio: mode=Mode.AUTO, asyncio_default_fixture_loop_scope=session
collected 2 items

test_demo.py test1 1592080607312
.test2 1592108632464
.

=========================================================== warnings summary =========================================================== 
..\.venv\Lib\site-packages\_pytest\config\__init__.py:1441
  C:\Users\Abon\Documents\Code\Projects\python\dev\.venv\Lib\site-packages\_pytest\config\__init__.py:1441: PytestConfigWarning: Unknown config option: asyncio_default_test_loop_scope

    self._warn_or_fail_if_strict(f"Unknown config option: {key}\n")

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
===================================================== 2 passed, 1 warning in 0.03s ===================================================== 

[Novakov]

Is this feature currently available in pytest-asyncio>=0.25.2?

Unfortunately it was merged after 0.25.2 was released.

[jassa]

looks like it also didn't make it into 0.25.3 but this made my tests much cleaner

# requirements.txt
pytest-asyncio @ git+https://github.com/pytest-dev/pytest-asyncio@e8de4dc37a707be7d040609c47ec477bab681f29

# pytest.ini
[pytest]
asyncio_mode = auto
asyncio_default_test_loop_scope = session
asyncio_default_fixture_loop_scope = session

# contest.py
@pytest.fixture(scope="session", autouse=True)
async def my_test_session_helper():
    ...

$ pytest
configfile: pytest.ini
plugins: asyncio-0.25.3.dev12+ge8de4dc, anyio-4.4.0
asyncio: mode=auto, asyncio_default_fixture_loop_scope=session, asyncio_default_test_loop_scope=session
collected ...