def METHOD_NAME(self):
    """Registering an external key/value will allow it to be included in
    the list returned by config_option_list action."""
    key = "ckanext.example_iconfigurer.test_conf"
    value = "Test value"
    params = {key: value}
    # add registered external value
    helpers.call_action("config_option_update", **params)
    option_list = helpers.call_action("config_option_list")
    assert key in option_list