Test

StartGame spyStartGame = spy(new StartGame());
    User user = mock(User.class);
    ISFSObject resObj = SFSObject.newInstance();
    resObj.putInt("res", 1);

    doNothing().when(spyStartGame).send("StartGame", resObj, user);
    spyStartGame.handleClientRequest(user, null);

    verify(spyStartGame).send("StartGame", resObj, user);