code: def test_source_format_check_should_throw_ex_when_incorrect_source_type(
      self,
      hook,
  ):
      hook.return_value.insert_job.side_effect = [
          MagicMock(job_id=pytest.real_job_id, error_result=False),
          pytest.real_job_id,
      ]
      hook.return_value.generate_job_id.return_value = (
          pytest.real_job_id
      )
      hook.return_value.split_tablename.return_value = (
          PROJECT_ID,
          DATASET,
          TABLE,
      )
      hook.return_value.get_job.return_value.result.return_value = (
          "1",
      )
  
      with pytest.raises(
          ValueError,
          match=r"is not a valid source format.",
      ):
          operator = GCSToBigQueryOperator(
              task_id=TASK_ID,
              bucket=TEST_BUCKET,
              source_objects=TEST_SOURCE_OBJECTS,
              destination_project_dataset_table=TEST_EXPLICIT_DEST,
              max_id_key=MAX_ID_KEY,
              write_disposition=WRITE_DISPOSITION,
              external_table=False,
              autodetect=False,
              source_format="incorrect",
              project_id=JOB_PROJECT_ID,
          )
          operator.execute(context=MagicMock())
  
imports: from __future__ import annotations
  import json
  from unittest import mock
  from unittest.mock import MagicMock, call
  import pytest
  from google.cloud.bigquery import DEFAULT_RETRY, Table
  from google.cloud.exceptions import Conflict
  from openlineage.client.facet import ColumnLineageDatasetFacet, ColumnLineageDatasetFacetFieldsAdditional, ColumnLineageDatasetFacetFieldsAdditionalInputFields, DocumentationDatasetFacet, ExternalQueryRunFacet, SchemaDatasetFacet, SchemaField, SymlinksDatasetFacet, SymlinksDatasetFacetIdentifiers
  from openlineage.client.run import Dataset
  from airflow.exceptions import AirflowException, TaskDeferred
  from airflow.models import DAG
  from airflow.models.dagrun import DagRun
  from airflow.models.taskinstance import TaskInstance
  from airflow.providers.google.cloud.transfers.gcs_to_bigquery import GCSToBigQueryOperator
  from airflow.providers.google.cloud.triggers.bigquery import BigQueryInsertJobTrigger
  from airflow.utils.timezone import datetime
  from airflow.utils.types import DagRunType
label_desc: Use image node_id 19 for calling the TestGCSToBigQueryOperator obj's underlying member method code with example usage: obj.test_source_format_check_should_throw_ex_when_incorrect_source_type(hook) without return types