def test_add_new_string_array_with_update_documents_api(self):
        """Test that adding new string arrays via update_documents fails.
        
        This test verifies that attempting to add new string arrays during an update operation
        results in appropriate error responses, as these field types cannot be added after 
        initial document creation.
        """
        # First add a minimal document with just an ID and a tensor field
        initial_doc = [{
            '_id': 'string_array_update_doc',
            'tensor_field': 'initial content'  # Need at least one field for indexing
        }]
        
        # Add the minimal document
        add_docs_response = self.client.index(self.text_index_name).add_documents(
            documents=initial_doc,
            tensor_fields=['tensor_field']
        )
        self.assertFalse(add_docs_response["errors"])
        
        # Try to update with a new string array
        update_docs_response = self.client.index(self.text_index_name).update_documents([{
            '_id': 'string_array_update_doc',
            'new_string_array': ['item1', 'item2']
        }])
        
        # Verify that errors were returned
        self.assertTrue(update_docs_response["errors"], 
                       "Expected error when adding new string array but got success")
        
        # Check the error details
        error_details = update_docs_response["items"][0]
        self.assertEqual(error_details["status"], 400, 
                        "Expected status code 400 for string array but got {error_details['status']}")

        # Assert the error message
        self.assertIn("Unstructured index updates only support updating existing string array fields"
                      , error_details["error"])
Test that adding new string arrays via update_documents fails.
        
        This test verifies that attempting to add new string arrays during an update operation
        results in appropriate error responses, as these field types cannot be added after 
        initial document creation.
        
tests/api_tests/v1/tests/api_tests/unstructured_index/test_update_documents_unstructured_index.py