Fix aiohttp test client cleanup

Author: tode-rl

tests/conftest.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import os
+import asyncio
 import logging
 from typing import TYPE_CHECKING, Iterator, AsyncIterator
 
@@ -111,3 +112,7 @@ async def async_client(request: FixtureRequest) -> AsyncIterator[AsyncRunloop]:
         base_url=base_url, bearer_token=bearer_token, _strict_response_validation=strict, http_client=http_client
     ) as client:
         yield client
+
+    # Give async transports a chance to finish closing before pytest collects
+    # unraisable ResourceWarnings under filterwarnings=error.
+    await asyncio.sleep(0.1)