SIENTIAPDE-1174

Refactor unit tests to improve readability and maintainability

- Updated test assertions and mock setups in test_app.py for clarity.
- Added 'pod_id' to the metadata in test_ingestor.py for consistency.
- Introduced a new test for TAG_WRITTEN_COUNT in test_metrics.py to verify its definition.
- Enhanced test data structure in test_data_manager.py to include additional fields.

tests/unit/managers/test_data_manager.py

@@ -10,6 +10,7 @@ metadata = {
         "model_name": "test_model",
         "workflow_name": "test_workflow",
         "schema_name": "test_schedule",
+        "pod_id": "localhost",
     },
 }
 
@@ -258,7 +259,10 @@ def test_publish_no_kafka(data_manager):
 @patch("ingestor.managers.data_manager.traceback")
 def test_publish_error(traceback, data_manager):
     topic = "test_topic"
-    data = {"key": "value"}
+    data = {
+        "key": "value",
+        "name": "test_tag"
+    }
 
     # Mock the send method of the Kafka producer to raise an exception
     send_mock = MagicMock(side_effect=Exception("Test error"))