fix error handling in request handler

Author: sokoliva

src/a2a/server/request_handlers/default_request_handler_v2.py

@@ -46,7 +46,6 @@
     PushNotificationNotSupportedError,
     TaskNotCancelableError,
     TaskNotFoundError,
-    UnsupportedOperationError,
 )
 from a2a.utils.helpers import maybe_await
 from a2a.utils.task import (
@@ -383,7 +382,7 @@ async def on_get_task_push_notification_config(  # noqa: D102
             if config.id == config_id:
                 return config
 
-        raise InternalError(message='Push notification config not found')
+        raise TaskNotFoundError
 
     @validate_request_params
     @validate(
@@ -418,7 +417,7 @@ async def on_list_task_push_notification_configs(  # noqa: D102
         context: ServerCallContext,
     ) -> ListTaskPushNotificationConfigsResponse:
         if not self._push_config_store:
-            raise UnsupportedOperationError
+            raise PushNotificationNotSupportedError
 
         task_id = params.task_id
         task: Task | None = await self.task_store.get(task_id, context)
@@ -445,7 +444,7 @@ async def on_delete_task_push_notification_config(  # noqa: D102
         context: ServerCallContext,
     ) -> None:
         if not self._push_config_store:
-            raise UnsupportedOperationError
+            raise PushNotificationNotSupportedError
 
         task_id = params.task_id
         config_id = params.id

tests/server/request_handlers/test_default_request_handler_v2.py

@@ -446,7 +446,7 @@ async def test_get_task_push_notification_config_info_not_found():
         task_id='non_existent_task', id='task_push_notification_config'
     )
     context = create_server_call_context()
-    with pytest.raises(InternalError):
+    with pytest.raises(TaskNotFoundError):
         await request_handler.on_get_task_push_notification_config(
             params, context
         )