def GetDataClient(mocked=False):
  """Returns a BigQueryClient with default credentials in the testing env."""
  if mocked:
    return mock_big_query_client.MockBigQueryClient(
        credential_file=credentials_lib.DEFAULT_CREDENTIALS,
        env=data_source_config.Environments.TESTING)
  else:
    return big_query_client.BigQueryClient(
        credential_file=credentials_lib.DEFAULT_CREDENTIALS,
        env=data_source_config.Environments.TESTING)