Java 初始化模拟对象 MockIto

使用流道或MockitoAnnotations.initMocks是严格等价的解决方案.从MockitoJUnitRunner个国家的javadoc:

JUnit 4.5 runner初始化用Mock注释的Mock，以便显式使用MockitoAnnotations.initMocks(对象)不是必需的.在每个测试方法之前，都会初始化模拟.

当您已经在测试用例上配置了特定的运行程序(例如SpringJUnit4ClassRunner)时，可以使用第一个解决方案(使用MockitoAnnotations.initMocks).

第二种解决方案(MockitoJUnitRunner)更classic ，也是我最喜欢的.代码更简单.使用流道提供了100的巨大优势(由this answer中的@David Wallace描述).

这两种解决方案都允许在测试方法之间共享模拟(和间谍).再加上@InjectMocks，它们可以非常快速地编写单元测试.样板模拟代码减少，测试更容易阅读.例如:

@RunWith(MockitoJUnitRunner.class)
public class ArticleManagerTest {

    @Mock private ArticleCalculator calculator;
    @Mock(name = "database") private ArticleDatabase dbMock;
    @Spy private UserProvider userProvider = new ConsumerUserProvider();

    @InjectMocks private ArticleManager manager;

    @Test public void shouldDoSomething() {
        manager.initiateArticle();
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        manager.finishArticle();
        verify(database).removeListener(any(ArticleListener.class));
    }
}

优点:代码非常简单

缺点:黑魔法.IMO这主要是由于@InjectMock注释造成的.使用此注释"you loose the pain of code"(请参阅@Brice的精彩注释)

第三个解决方案是在每个测试方法上创建您的模拟. 正如@mlk在其答复中所解释，它允许具有"self contained test".

public class ArticleManagerTest {

    @Test public void shouldDoSomething() {
        // given
        ArticleCalculator calculator = mock(ArticleCalculator.class);
        ArticleDatabase database = mock(ArticleDatabase.class);
        UserProvider userProvider = spy(new ConsumerUserProvider());
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.initiateArticle();

        // then 
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        // given
        ArticleCalculator calculator = mock(ArticleCalculator.class);
        ArticleDatabase database = mock(ArticleDatabase.class);
        UserProvider userProvider = spy(new ConsumerUserProvider());
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.finishArticle();

        // then
        verify(database).removeListener(any(ArticleListener.class));
    }
}

优点:你清楚地展示了你的api是如何工作的(BDD…)

缺点:有更多的样板代码.(模仿创作)

My建议是一种妥协.使用@Mock注释和@RunWith(MockitoJUnitRunner.class)注释，但不要使用@InjectMocks注释:

@RunWith(MockitoJUnitRunner.class)
public class ArticleManagerTest {

    @Mock private ArticleCalculator calculator;
    @Mock private ArticleDatabase database;
    @Spy private UserProvider userProvider = new ConsumerUserProvider();

    @Test public void shouldDoSomething() {
        // given
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.initiateArticle();

        // then 
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        // given
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.finishArticle();

        // then 
        verify(database).removeListener(any(ArticleListener.class));
    }
}

优点:你清楚地展示了你的api是如何工作的(my ArticleManager是如何实例化的).没有样板代码.

缺点:测试不是自包含的，代码痛苦较少