code: def test_parse_message_missing_fields(self, connector):
      # Test JSON content with missing fields
      with pytest.raises(ValueError):
          connector._parse_message(
              ChatMessage.from_assistant(
                  '[{"function": {"name": "test_method"}}]'
              )
          )
  
file_path: haystack/test/components/connectors/test_openapi_service.py
imports: import json
  import pytest
  from unittest.mock import MagicMock, Mock
  from openapi3 import OpenAPI
  from haystack.components.connectors import OpenAPIServiceConnector
  from haystack.dataclasses import ChatMessage
label_desc: Use image node_id 4 for calling the TestOpenAPIServiceConnector obj's underlying member method code with example usage: obj.test_parse_message_missing_fields(connector) without return types