[FIXED] "RuntimeWarning: coroutine was never awaited" in python tests

Issue

I run my python tests with pytest and it shows a warning:

RuntimeWarning: coroutine 'AsyncMockMixin._execute_mock_call' was never awaited

In the first glance I didn't see problems with my code. All coroutines were awaited as far as I can see. But obviously there is some problem in tests.

How my test looks like. I deleted some info to hide business logic.

@pytest.mark.asyncio()
async def test1(
    client: httpx.AsyncClient,
    mock1: MagicMock, ...
) -> None:
    ...
    await client.post(url="url", json=jsonable_encoder(body.dict(), by_alias=True))
    mock1.func.assert_awaited_once_with(...)

As docs recommends, I've enabled tracemalloc. But it only shows this info:

.../lib/python3.11/site-packages/fastapi/routing.py:144: RuntimeWarning: coroutine 'AsyncMockMixin._execute_mock_call' was never awaited
    value, errors_ = field.validate(response_content, {}, loc=("response",))
  
  Object allocated at:
    File ".../lib/python3.11/site-packages/pluggy/_callers.py", line 77
      res = hook_impl.function(*args)
    File ".../lib/python3.11/site-packages/_pytest/runner.py", line 169
      item.runtest()
    File ".../lib/python3.11/site-packages/_pytest/python.py", line 1792
      self.ihook.pytest_pyfunc_call(pyfuncitem=self)
    File ".../lib/python3.11/site-packages/pluggy/_hooks.py", line 493
      return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
    File ".../lib/python3.11/site-packages/pluggy/_manager.py", line 115
      return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
    File ".../lib/python3.11/site-packages/pluggy/_callers.py", line 77
      res = hook_impl.function(*args)
    File ".../lib/python3.11/site-packages/_pytest/python.py", line 194
      result = testfunction(**testargs)
    File ".../lib/python3.11/site-packages/pytest_asyncio/plugin.py", line 532
      _loop.run_until_complete(task)
    File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 640
      self.run_forever()
    File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 607
      self._run_once()
    File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 1922
      handle._run()
    File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/events.py", line 80
      self._context.run(self._callback, *self._args)
    File ".../lib/python3.11/site-packages/starlette/middleware/base.py", line 70
      await self.app(scope, receive_or_disconnect, send_no_error)
    File ".../lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 68
      await self.app(scope, receive, sender)
    File ".../lib/python3.11/site-packages/fastapi/middleware/asyncexitstack.py", line 17
      await self.app(scope, receive, send)
    File ".../python3.11/site-packages/starlette/routing.py", line 718
      await route.handle(scope, receive, send)
    File ".../lib/python3.11/site-packages/starlette/routing.py", line 276
      await self.app(scope, receive, send)
    File ".../lib/python3.11/site-packages/starlette/routing.py", line 66
      response = await func(request)
    File ".../lib/python3.11/site-packages/fastapi/routing.py", line 291
      content = await serialize_response(
    File ".../lib/python3.11/site-packages/fastapi/routing.py", line 144
      value, errors_ = field.validate(response_content, {}, loc=("response",))

But it's fastapi package. I don't think, that the problem is there

What my possible next steps to catch where exactly not awaited coroutine created in my code? Please, recommend some tools or commands.

Solution

Turned out that this warning was appearing because result of function client.post was never assigned to any variable.

So I changed my test to

@pytest.mark.asyncio()
async def test1(
    client: httpx.AsyncClient,
    mock1: MagicMock, ...
) -> None:
    ...
    resp = await client.post(url="url", json=jsonable_encoder(body.dict(), by_alias=True))
    assert resp.status_code == 200
    mock1.func.assert_awaited_once_with(...)

And warning was gone.

Answered By - puf