[BUG] pytest hangs when using async_get_injected_obj

[Nemesis7]

Describe the bug
So I cannot pinpoint it just yet, but when using async_get_injected_obj to load a class e.g. self.handler = await async_get_injected_obj(HandlerClass), it will hang when running pytest via command line poetry run pytest tests\handlers.py

Now I've switched back to an old implementation to load these classes (can't remember where I found this) and it just works:

async def solve_command(request: Request, dependant: Dependant) -> Any:
    """
    Helper function to solve dependencies.
    """
    async with AsyncExitStack() as cm:
        solved_dependency = await solve_dependencies(
            request=request, dependant=dependant, embed_body_fields=False, async_exit_stack=cm
        )
        values = solved_dependency.values
        errors = solved_dependency.errors
        if errors:
            raise ValidationError(errors, None)
        if inspect.iscoroutinefunction(dependant.call):
            result = await dependant.call(**values)
        else:
            result = dependant.call(**values)  # type: ignore

        return result


async def load_with_dependencies(command: Callable) -> Any:
    """
    Wrapper which creates a fake Request to resolve all dependencies within a class,
    using the dependency injection offered by FastAPI.
    """
    async with AsyncExitStack() as cm:
        request = Request({"type": "http", "headers": [], "query_string": "", "fastapi_astack": cm})

        dependant = get_dependant(path="command", call=command, use_cache=False)

        return await solve_command(request, dependant)

pytest just hangs, and nothing happens, no error, no timeout. Also because I'm using httpx, I needed to add this in the pyproject.toml file:

# needed when using httpx, see https://github.com/pytest-dev/pytest-asyncio/issues/868
asyncio_default_fixture_loop_scope = "session"
asyncio_default_test_loop_scope = "session"

Note that the tests just work in sequence when ran from the IDE (IntelliJ IDEA), but not when run via pytest.

To Reproduce
So I don't know how to reproduce, except that it breaks if there are multiple tests with multiple api calls

Expected behavior
I'd expect the pytest tests to run as expected

Screenshots

OS
macosx Tahoe 26.1

Version

1. Python: 3.13
2. FastAPI: 0.120.4

[rod7760]

A minimal reproducible example is probably needed to diagnose this.

[JasperSui]

@Nemesis7 I'm assuming you're using pytest-asyncio with asynchronous test cases, if so, please try to upgrade it to v1.2.0 or higher, and follow these existing test cases and pyproject settings to see if they help.

[Nemesis7]

@Nemesis7 I'm assuming you're using pytest-asyncio with asynchronous test cases, if so, please try to upgrade it to v1.2.0 or higher, and follow these existing test cases and pyproject settings to see if they help.

I'm using pytest-asyncio indeed, I was already on 1.2.0, I upgraded to 1.3.0, same results. I will come up with something to reproduce, haven't had the time yet.

[Nemesis7]

Ok, update. Like I mentioned, it's hard to reproduce the problem with an example, but my pytest setup looks something like this:

async def setup(self) -> None:
    self.handler = await async_get_injected_obj(EventHandler)  # type: ignore[arg-type]
    
async def test_scenario_1(self) -> None:
    await self.handler.handle({})

async def test_scenario_2(self) -> None:
    await self.handler.handle({})

Now when I run my tests like this, it hangs at the 5th test. I noticed that when I pass use_cache=False to async_get_injected_obj, it doesn't hang. Hopefully that helps in finding the issue.

[rod7760]

@Nemesis7 What version of pytest are you using?

edit:

Actually, providing the whole header for your pytest run would probably help:

platform linux -- Python 3.13.7, pytest-8.3.5, pluggy-1.6.0
rootdir: /home/rick/Projects/scratch
plugins: asyncio-1.3.0, anyio-4.12.0
asyncio: mode=Mode.STRICT, debug=False, asyncio_default_fixture_loop_scope=session, asyncio_default_test_loop_scope=session
collected 5 items  

[Nemesis7]

Sure, here it is:

platform darwin -- Python 3.13.9, pytest-8.4.2, pluggy-1.6.0 -- /Users/nemesis7/Library/Caches/pypoetry/virtualenvs/<redacted>-3_4FF3K--py3.13/bin/python
cachedir: .pytest_cache
rootdir: /Users/nemesis7/dev/<redacted>
configfile: pyproject.toml
plugins: anyio-4.11.0, httpx-0.35.0, vcr-1.0.2, django-de-testsupport-4.2.2, asyncio-1.3.0, cov-7.0.0
asyncio: mode=Mode.AUTO, debug=False, asyncio_default_fixture_loop_scope=session, asyncio_default_test_loop_scope=session

[rod7760]

I am unable to recreate this based on the information provided.

If not caching resolves it for you, then you probably have tests sharing state they shouldn't.

This was my attempt:

# /// script
# requires-python = ">=3.12"
# dependencies = [
#     "fastapi-injectable==1.4.2",
#     "pytest==8.4.2",
#     "anyio==4.11.0",
#     "pytest-asyncio==1.3.0",
# ]
# ///
from typing import Annotated

import pytest
from fastapi import Depends

import unittest

from fastapi_injectable.util import async_get_injected_obj


class Database:
    async def query(self) -> str:
        return "data"

def get_db() -> Database:
    return Database()

async def async_get_db(db: Annotated[Database, Depends(get_db)]) -> Database:
    return db


class TestGroup(unittest.IsolatedAsyncioTestCase):
    async def asyncSetUp(self):
        self.db = await async_get_injected_obj(get_db)
    @pytest.mark.asyncio
    async def test_1(self):
        assert await self.db.query() == "data"
    @pytest.mark.asyncio
    async def test_2(self):
        assert await self.db.query() == "data"

uv run --python 3.13 --with-requirements pytest-async-fastapi-injectable.py pytest --asyncio-mode=auto -o asyncio_default_fixture_loop_scope=session -o asyncio_default_test_loop_scope=session pytest-async-fastapi-injectable.py

[JasperSui]

@Nemesis7

I suspect this issue might be caused by some async exit stacks not being cleaned up properly, leading to lingering resources or tasks that prevent the event loop from closing.

The fastest way to verify this is to add a pytest fixture with autouse=True that ensures cleanup_all_exit_stacks()is called after each test case. You can try adding this to your conftest.py or test file:

import pytest
from fastapi_injectable import cleanup_all_exit_stacks

@pytest.fixture(autouse=True)
async def cleanup_dependencies():
    yield
    # Force cleanup of all exit stacks after each test
    await cleanup_all_exit_stacks()

Could you try this and see if the tests still hang?

[Nemesis7]

Hi @JasperSui, I have tried your suggestion, but it hangs again, reverting back to not using cache. Thanks for the thinking along, I know it's very little to go on.

[JasperSui]

Hi @Nemesis7, please try 1.5.0 and see if it's resolved, thanks!