refactor: improve mocking utilities for RPC interfaces in tests

Author: pcrespov

services/api-server/tests/unit/api_functions/celery/conftest.py

@@ -52,19 +52,18 @@ async def mocked_log_streamer_setup(mocker: MockerFixture) -> MockerFixture:
     # mock log streamer: He is looking for non-existent queues. Should be solved more elegantly
     from simcore_service_api_server.services_http import rabbitmq
 
-    mock_log_streamer = mocker.patch.object(rabbitmq, "LogDistributor", spec=True)
-    return mock_log_streamer
+    return mocker.patch.object(rabbitmq, "LogDistributor", spec=True)
 
 
 @pytest.fixture
 def mock_celery_app(mocker: MockerFixture, celery_config: dict[str, Any]) -> Celery:
     celery_app = Celery(**celery_config)
 
-    mocker.patch.object(
+    mock = mocker.patch.object(
         celery_task_manager,
         celery_task_manager.create_app.__name__,
-        lambda settings: celery_app,
     )
+    mock.return_value = celery_app
 
     return celery_app