Mockito如何捕获传递给注入的模拟对象方法的参数？

问题描述

我正在尝试测试一个服务类，它在内部使用Spring AMQP连接对象。此连接对象由Spring注入。但是，我不希望我的单元测试实际上与AMQP代理通信，因此我使用Mockito注入连接对象的模拟。

I am trying to test a service class, which internally makes use of a Spring AMQP connection object. This connection object is injected by Spring. However, I don't want my unit test to actually communicate with the AMQP broker, so I am using Mockito inject a mock of the connection object.

/** 
 * The real service class being tested.  Has an injected dependency. 
 */ 
public class UserService {

   @Autowired
   private AmqpTemplate amqpTemplate;

   public final String doSomething(final String inputString) {
      final String requestId = UUID.randomUUID().toString();
      final Message message = ...;
      amqpTemplate.send(requestId, message);
      return requestId;
   }
}

/** 
 * Unit test 
 */
public class UserServiceTest {

   /** This is the class whose real code I want to test */
   @InjectMocks
   private UserService userService;

   /** This is a dependency of the real class, that I wish to override with a mock */
   @Mock
   private AmqpTemplate amqpTemplateMock;

   @Before
   public void initMocks() {
      MockitoAnnotations.initMocks(this);
   }

   @Test
   public void testDoSomething() {
      doNothing().when(amqpTemplateMock).send(anyString(), any(Message.class));

      // Call the real service class method, which internally will make 
      // use of the mock (I've verified that this works right).
      userService.doSomething(...);

      // Okay, now I need to verify that UUID string returned by 
      // "userService.doSomething(...) matches the argument that method 
      // internally passed to "amqpTemplateMock.send(...)".  Up here 
      // at the unit test level, how can I capture the arguments passed 
      // to that inject mock for comparison?
      //
      // Since the value being compared is a UUID string created 
      // internally within "userService", I cannot just verify against 
      // a fixed expected value.  The UUID will by definition always be
      // unique.
   }
}

这个代码示例中的注释有希望清楚地说明问题。当Mockito将一个模拟依赖项注入一个真正的类，并且对真实类的单元测试导致它调用mock时，你怎么能在以后检索到的确切参数传递到注入的模拟？

The comments in this code sample hopefully lay out the question clearly. When Mockito injects a mock dependency into a real class, and unit tests on the real class cause it to make calls to the mock, how can you later retrieve the exact arguments that were passed to the injected mock?

推荐答案

使用一个或多个 ArgumentCaptor s。

目前还不清楚你的类型是什么在这里，但无论如何。假设你有一个模拟器，它有一个方法 doSomething（）以 Foo 作为参数，然后你这样做：

It is unclear what your types are here, but anyway. Let's suppose you have a mock which has a method doSomething() taking a Foo as an argument, then you do this:

final ArgumentCaptor<Foo> captor = ArgumentCaptor.forClass(Foo.class);

verify(mock).doSomething(captor.capture());

final Foo argument = captor.getValue();

// Test the argument

此外，看起来您的方法返回无效，你不希望它做任何事情。只需写下：

Also, it looks like your method returns void and you don't want it to do anything. Just write this:

doNothing().when(theMock).doSomething(any());

这篇关于Mockito如何捕获传递给注入的模拟对象方法的参数？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！