java - 使用Mockito但运行测试用例时出现空指针异常

Question

我正在尝试使用 selenium webelement 作为参数为该函数创建测试用例 junit。

我正在尝试模拟该元素，但此测试用例给出错误。我尝试制作测试用例的方法是这样的。

 @Override
    public boolean isDownloadStarted(WebDriver driver) {
        boolean isDownloadStarted = false;
        ArrayList<String> tabs = new ArrayList<>(driver.getWindowHandles());
        if (tabs.size() == 1) {
            isDownloadStarted = true;
        }
        return isDownloadStarted;
    }

测试用例给出了空指针异常

DownloadStatusListenerImpl status;

@Before
public void before() {
    MockitoAnnotations.initMocks(this);
    status = new DownloadStatusListenerImpl();
}
@Test
    public void testDownloadStatusListenerImpl() {
        Mockito.when(status.isDownloadStarted(Mockito.any(WebDriver.class))).thenReturn(true);
        assertEquals(true, status.isDownloadStarted(Mockito.any(WebDriver.class)));
    }

Answer 1

您没有 stub 状态。您可以向其添加 @Spy 注释(并停止覆盖它):

@Spy // Annotation added here
DownloadStatusListenerImpl status;

@Before
public void before() {
    MockitoAnnotations.initMocks(this);
    // Stopped overwriting status here
}

或者您可以显式调用Mockito.spy:

@Before
public void before() {
    status = Mockito.spy(new DownloadStatusListenerImpl());
}

编辑:

在这样的方法上调用 when 仍然会调用它，从而失败。您需要改用 doReturn 语法:

Mockito.doReturn(true).when(status).isDownloadStarted(Mockito.any(WebDriver.class));