def METHOD_NAME(self, mock_load_rules_from_gcs):
    """Test that a RuleBook is built correctly with a mocked gcs file.
    Setup:
        * Create a mocked GCS object from a test yaml file.
        * Get the yaml file content.
    Expected results:
        There are 4 resources that have rules, in the rule book.
    """
    bucket_name = 'bucket-name'
    rules_path = 'input/buckets_test_rules_1.yaml'
    full_rules_path = 'gs://{}/{}'.format(bucket_name, rules_path)
    rules_engine = bre.BucketsRulesEngine(rules_file_path=full_rules_path)
    # Read in the rules file
    file_content = None
    with open(get_datafile_path(__file__, 'buckets_test_rules_1.yaml'),
              'r') as rules_local_file:
        try:
            file_content = yaml.safe_load(rules_local_file)
        except yaml.YAMLError:
            raise
    mock_load_rules_from_gcs.return_value = file_content
    rules_engine.build_rule_book()
    self.assertEqual(2, len(rules_engine.rule_book.resource_rules_map))