如何模拟 @InjectMocks 类的方法?

2022-01-14 00:00:00 mocking unit-testing mockito java

例如我有处理程序:

@Component
public class MyHandler {

  @AutoWired
  private MyDependency myDependency;

  public int someMethod() {
    ...
    return anotherMethod();
  }

  public int anotherMethod() {...}
}

为了测试它，我想写这样的东西:

to testing it I want to write something like this:

@RunWith(MockitoJUnitRunner.class}
class MyHandlerTest {

  @InjectMocks
  private MyHandler myHandler;

  @Mock
  private MyDependency myDependency;

  @Test
  public void testSomeMethod() {
    when(myHandler.anotherMethod()).thenReturn(1);
    assertEquals(myHandler.someMethod() == 1);
  }
}

但每当我尝试模拟它时，它实际上都会调用 anotherMethod() .我应该用 myHandler 做什么来模拟它的方法?

But it actually calls anotherMethod() whenever I try to mock it. What should I do with myHandler to mock its methods?

推荐答案

首先mock MyHandler方法的原因可能如下:我们已经测试过anotherMethod()，它的逻辑很复杂，那么，如果我们可以verify 它正在调用，为什么我们需要再次测试它(就像 someMethod() 的一部分)?
我们可以通过:

First of all the reason for mocking MyHandler methods can be the following: we already test anotherMethod() and it has complex logic, so why do we need to test it again (like a part of someMethod()) if we can just verify that it's calling?
We can do it through:

@RunWith(MockitoJUnitRunner.class)
class MyHandlerTest {

  @Spy  
  @InjectMocks  
  private MyHandler myHandler;  

  @Mock  
  private MyDependency myDependency;  

  @Test  
  public void testSomeMethod() {  
    doReturn(1).when(myHandler).anotherMethod();  
    assertEquals(myHandler.someMethod() == 1);  
    verify(myHandler, times(1)).anotherMethod();  
  }  
}

注意:在 'spying' 对象的情况下，我们需要使用 doReturn 而不是 thenReturn(小解释是 这里)

Note: in case of 'spying' object we need to use doReturn instead of thenReturn(little explanation is here)

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