def METHOD_NAME(mocker: MockerFixture) -> None:
    """
    Test the ``get_extra_params`` method.
    """
    from superset.db_engine_specs.snowflake import SnowflakeEngineSpec
    database = mocker.MagicMock()
    database.extra = {}
    assert SnowflakeEngineSpec.get_extra_params(database) == {
        "engine_params": {"connect_args": {"application": "Apache Superset"}}
    }
    database.extra = json.dumps(
        {
            "engine_params": {
                "connect_args": {"application": "Custom user agent", "foo": "bar"}
            }
        }
    )
    assert SnowflakeEngineSpec.get_extra_params(database) == {
        "engine_params": {
            "connect_args": {"application": "Custom user agent", "foo": "bar"}
        }
    }