基于Consumer功能接口的单元测试回调

Question

我正在尝试对在 Consumer 功能接口中作为回调运行的代码进行单元测试。

@Component
class SomeClass {

  @Autowired
  private SomeInteface toBeMockedDependency;

  public method() {
     toBeMockedDependency.doSomething(message -> {
        // Logic under test goes here 
        //             (implements java.util.function.Consumer interface)
        ...
     });
  }
}

@RunWith(MockitoJUnitRunner.class)
public class SomeClassTest {
  @InjectMocks
  private SomeClass someClass;
  @Mock
  private SomeInteface toBeMockedDependency;

  @Test
  public void testMethod() {
    ...
    someClass.method();
    ...
  }
}

本质上，我想通过“toBeMockedDependency”向测试代码提供一些经过测试的“消息”。

如何模拟“toBeMockedDependency”以提供预定义的消息？
这是正确的方法吗？

Answer 1

不要试图使toBeMockedDependency自动调用您的功能接口。相反，使用 a@Captor来捕获匿名功能接口，然后使用您的测试手动调用它。

@RunWith(MockitoJUnitRunner.class)
public class SomeClassTest {
  @InjectMocks
  private SomeClass someClass;
  @Mock
  private SomeInteface toBeMockedDependency;
  @Captor
  private ArgumentCaptor<Consumer<Message>> messageConsumerCaptor;

  @Test
  public void testMethod() {
    someClass.method();
    verify(toBeMockedDependency).doSomething(messageConsumerCaptor.capture());
    Consumer<Message> messageConsumer = messageConsumerCaptor.getValue();

    // Now you have your message consumer, so you can test it all you want.
    messageConsumer.accept(new Message(...));
    assertEquals(...);
  }
}