def METHOD_NAME(
    decoy: Decoy, subject: MagneticModuleCore, mock_engine_client: EngineClient
) -> None:
    """It should return a serial number."""
    decoy.when(mock_engine_client.state.modules.get_serial_number("1234")).then_return(
        "abc"
    )
    assert subject.get_serial_number() == "abc"