Question

我想测试从Player类调用setter方法的方法randomPlayerStart。我创建了一个测试用例，用于检查播放器的boolean值。

@Before
public void setUp() throws Exception {
    playerA = new Player("Player A", false);
    playerB = new Player("Player B", false);
    activity = new MainActivity();
    activity.randomPlayerStart();
}

@Test
public void testrandomPlayerStart() throws Exception {
    assertEquals(true,playerB.isTurn());
}

这是randomPlayerStart方法。

public void randomPlayerStart() {
    Random random = new Random();
    boolean player = random.nextBoolean();

    if (player) {
        playerA.setTurn(true);
    } else {
        playerB.setTurn(true);
    }
}

我已经尝试了overriding测试文件中的方法，并试图从mockito框架中使用Spy，但它没有用。当我使用doNothing而不是doAnswer时，我没有收到nullException错误，但是该方法没有调用。

@Before
public void setUp() throws Exception {
    Turn = false;
    playerA = new Player("Player A", false) {
        public void setTurn(boolean turn) {
            Turn = turn;
        }
    };
    playerB = new Player("Player B", false) {
        public void setTurn(boolean turn) {
            Turn = turn;
        }
    };
    activity = new MainActivity() {
        public void randomPlayerStart() {
            Random random = new Random();
            boolean player = random.nextBoolean();

            if (player) {
                playerA.setTurn(true);
            } else {
                playerB.setTurn(true);
            }
        }
    };
    MainActivity spy = Mockito.spy(activity);

    doAnswer(new Answer() {
        @Override
        public Object answer(InvocationOnMock invocation) throws Throwable {
            activity.randomPlayerStart();
            return null;
        }
    }).when(spy).randomPlayerStart();
    spy.randomPlayerStart();
}

我不确定接下来要尝试什么，我没有测试经验，因此非常感谢任何评论或指示。

Answer 1

如果您将Random移到randomPlayerStart之外，那么您可以mock然后轻松测试您的方法。

//omitted declarations

Random random;

@Before
public void setUp() throws Exception {
    playerA = new Player("Player A", false);
    playerB = new Player("Player B", false);
    activity = new MainActivity();

    random = mock(Random.class); //static import of Mockito.mock
}

@Test
public void testRandomPlayerStart_playerA() throws Exception {
    when(random.nextBoolean()).thenReturn(Boolean.TRUE); //static import of Mockito.when

    activity.randomPlayerStart(random);
    assertEquals(true,playerA.isTurn());
}

@Test
public void testRandomPlayerStart_playerB() throws Exception {
    when(random.nextBoolean()).thenReturn(Boolean.FALSE);

    activity.randomPlayerStart(random);
    assertEquals(true,playerB.isTurn());
}

您的randomPlayerStart需要接受随机参数 public void randomPlayerStart(Random random)

一旦将依赖关系移到外面测试就容易多了，不是吗？：）

Answer 2

发表评论njzk2。我决定创建另一个类（MainActivity presenter），它接受三个值，一个接口和两个播放器对象。

public class MainActivityPresenter {
MainActivityView view;
Player playerA, playerB;


public MainActivityPresenter(MainActivityView view, Player playerA, Player playerB) {


    this.view = view;
    this.playerA = playerA;
    this.playerB = playerB;

}

public void randomPlayerStart() {
    Random random = new Random();
    boolean player = random.nextBoolean();

    if (player) {
        playerA.setTurn(true);
    } else {
        playerB.setTurn(true);


    }
}

public void initPlayers() {
    playerA = new Player("Player A", false);
    playerB = new Player("Player B", false);
    }
}

然后我创建了一个我在MainActivity类中实现的接口。现在可以实例化MainActivityPresenter类。

public void startGame(){
    initPlayers();
    linkIds();
    initBtns();
    initCells();
    initLinkedList();
    randomPlayerStart();
    hand = new Hand(0);

    switchTurn();
    presenter = new MainActivityPresenter(MainActivity.this, playerA, playerB );



}
public void randomPlayerStart() {
    presenter.randomPlayerStart();
}

这意味着我可以通过实例化MainActivityPresenter类而不是MainActivity类从测试类中调用randomPlayerStart（）方法，而不会出现NullException错误。

谢谢大家

JUnit调用调用另一个方法的方法返回nullPointerException

2 个答案: