def METHOD_NAME(self):
    """Tests that the config file is valid."""
    config_file = os.path.join("data", "features.yaml")
    self.assertTrue(os.path.isfile(config_file))
    with open(config_file) as fh:
        config = yaml.safe_load(fh)
    self.assertIsInstance(config, dict)
    for key, value in iter(config.items()):
        self.assertIsInstance(key, str)
        self.assertIsInstance(value, dict)
        self._config_validation(value)