Fix voice STT task cleanup to properly await cancelled tasks

Problem: The _cleanup_tasks() method in OpenAISTTTranscriptionSession was only calling task.cancel() on pending tasks (listener, process_events, stream_audio, connection) but not awaiting them. This could lead to: 1. Unhandled task exception warnings 2. Potential resource leaks (websocket connections, file descriptors) 3. Improper cleanup of background tasks Evidence: - Similar to the recently fixed guardrail tasks cleanup (PR #1976) - Similar to the fixed websocket task cleanup (PR #1955) - asyncio best practices require awaiting cancelled tasks Solution: 1. Made _cleanup_tasks() async 2. Collect all real asyncio.Task objects that need to be awaited 3. Added await asyncio.gather() with return_exceptions=True to properly collect exceptions from cancelled tasks 4. Updated close() method to await _cleanup_tasks() Testing: - All existing voice/STT tests pass (17 passed) - Uses isinstance check to support mock objects in tests - Follows the same pattern as PR #1976 and PR #1955

Author: gn00295120

src/agents/voice/models/openai_stt.py

@@ -321,18 +321,37 @@ def _check_errors(self) -> None:
 ifexcandisinstance(exc, Exception):
 self._stored_exception=exc
 
-def_cleanup_tasks(self) ->None:
+asyncdef_cleanup_tasks(self) ->None:
+"""Cancel all pending tasks and wait for them to complete.
+
+ This ensures that any exceptions raised by the tasks are properly handled
+ and prevents warnings about unhandled task exceptions.
+ """
+tasks= []
+
 ifself._listener_taskandnotself._listener_task.done():
 self._listener_task.cancel()
+ifisinstance(self._listener_task, asyncio.Task):
+tasks.append(self._listener_task)
 
 ifself._process_events_taskandnotself._process_events_task.done():
 self._process_events_task.cancel()
+ifisinstance(self._process_events_task, asyncio.Task):
+tasks.append(self._process_events_task)
 
 ifself._stream_audio_taskandnotself._stream_audio_task.done():
 self._stream_audio_task.cancel()
+ifisinstance(self._stream_audio_task, asyncio.Task):
+tasks.append(self._stream_audio_task)
 
 ifself._connection_taskandnotself._connection_task.done():
 self._connection_task.cancel()
+ifisinstance(self._connection_task, asyncio.Task):
+tasks.append(self._connection_task)
+
+# Wait for all cancelled tasks to complete and collect exceptions
+iftasks:
+awaitasyncio.gather(*tasks, return_exceptions=True)
 
 asyncdeftranscribe_turns(self) ->AsyncIterator[str]:
 self._connection_task=asyncio.create_task(self._process_websocket_connection())
@@ -367,7 +386,7 @@ async def close(self) -> None:
 ifself._websocket:
 awaitself._websocket.close()
 
-self._cleanup_tasks()
+awaitself._cleanup_tasks()
 
 
 classOpenAISTTModel(STTModel):