java - 模拟链式调用

Question

被测试的类是 TestedClass，它包含 InnerClass 类型中名为“inner”的字段。

Class TestedClass{

  InnerClass inner;

  public void methodToTest() {
     inner.getSomething().AddSomething(new Something());
  }
}

在我的测试中，我为“内部”创建了一个模拟，但无法弄清楚如何测试 methodToTest，我尝试过的所有选项要么不编译，要么从 Mockito 获取异常。模拟和测试此场景的正确方法是什么？

谢谢。

Answer 1

您应该在 TestedClass 初始化期间注入(inject) InnerClass 模拟。例如，您应该有一个构造函数:

class Something {
    void addSomething(Something sth) {
    }
}

class InnerClass {
    Something getSomething() {
        return new Something();
    }
}

class TestClass {

    private final InnerClass inner;

    TestClass(InnerClass inner) {
        this.inner = inner;
    }

    public void methodToTest() {
        inner.getSomething().addSomething(new Something());
    }
}

验证调用的测试将是:

@Test
public void shouldInvokeInnerClassMethod() {
    InnerClass innerMock = Mockito.mock(InnerClass.class);
    TestClass testSubject = new TestClass(innerMock);

    testSubject.methodToTest();

    verify(innerMock).getSomething();
}

如果您想测试传递给 addSometing 方法的值:

@Test
public void shouldAddSomething() {
    ArgumentCaptor<Something> somethingCaptor = ArgumentCaptor.forClass(Something.class);
    Something somethingMock = Mockito.mock(Something.class);
    InnerClass innerMock = Mockito.mock(InnerClass.class);
    when(innerMock.getSomething()).thenReturn(somethingMock);
    TestClass testSubject = new TestClass(innerMock);

    testSubject.methodToTest();

    verify(somethingMock).addSomething(somethingCaptor.capture());
    Something addedSomething = somethingCaptor.getValue();
    //assertions on addedSomething content
}