refactor(server/events): improve event parsing and update test assertions

- Add type annotation for parsed event in RedisQueueManager
- Update test assertions to check tap call count in queue manager tests

Author: long.qul

src/a2a/server/events/redis_queue_manager.py

@@ -132,7 +132,7 @@ async def _relay_remote_events(self, subscription_event: dict[str, Any]) -> None
 
         try:
             logger.debug(f"Received event for task_id {task_id} in QM {self}: {data_string}")
-            event = TypeAdapter(Event).validate_json(data_string)
+            event: Event = TypeAdapter(Event).validate_json(data_string)
         except Exception as e:
             logger.warning(f"Failed to parse event from subscription event: {subscription_event}: {e}")
             return

tests/server/events/test_redis_queue_manager.py

@@ -64,10 +64,11 @@ async def test_get_nonexistent_queue(self, queue_manager):
     async def test_tap_existing_queue(self, queue_manager, event_queue):
         task_id = 'test_task_id'
         await queue_manager.add(task_id, event_queue)
+        event_queue.tap.assert_called_once()
 
         result = await queue_manager.tap(task_id)
         assert result == event_queue
-        event_queue.tap.assert_called_once()
+        assert event_queue.tap.call_count == 2
 
     @pytest.mark.asyncio
     async def test_tap_nonexistent_queue(self, queue_manager):
@@ -88,11 +89,12 @@ async def test_create_or_tap_existing_queue(
     ):
         task_id = 'test_task_id'
         await queue_manager.add(task_id, event_queue)
+        event_queue.tap.assert_called_once()
 
         result = await queue_manager.create_or_tap(task_id)
 
         assert result == event_queue
-        event_queue.tap.assert_called_once()
+        assert event_queue.tap.call_count == 2
 
     @pytest.mark.asyncio
     async def test_concurrency(self, queue_manager):