java - mockito spy 可以返回 stub 值吗？

Question

我想测试这个类，所以它会告诉我我用正确的参数调用了 ws:

class MyService {
  public static boolean sendEmail(MyWebService ws) {
      if (!ws.sendCustomEmail("me@example.com", "Subject", "Body")) {
          throw new RuntimeException("can't do this");
      }
      // ... some more logic which can return false and should be tested
      return true;
  }
}

有没有办法结合 mockito spy 和 thenReturn？我喜欢 spy 显示实际方法调用的方式，而不仅仅是有关 assertionFailed 的简单消息。

@Test
void myTest() {
  MyService spyWs = Mockito.spy(MyWebService.class);

  // code below is not working, but I wonder if there is some library
  verify(spyWs, once())
    .sendCustomEmail(
        eq("me@example.com"), 
        eq("Subject"), 
        eq("here should be another body and test shou")
    )
    .thenReturn(true);

  MyService::sendEmail(spyWs);
}

结果我想要的是错误消息向我展示参数之间的差异，就像通常的 spy 一样:

Test failed: 
sendCustomEmail(eq("me@example.com"), eq("Subject"), eq("here should be another body and test should show diff")) was never called
sendCustomEmail(eq("me@example.com"), eq("Subject"), eq("Body")) was called, but not expected

预期:

• 我知道我可以只做 stub 然后测试异常，但这不会显示参数的差异

Answer 1

使用Spy 时，请使用doReturn().when() 语法。还要在设置后验证:

MyService spyWs = Mockito.spy(MyWebService.class);

doReturn(true).when(spyWs).sendCustomEmail(any(), any(), any());

MyService::sendEmail(spyWs);

verify(spyWs, once())
   .sendCustomEmail(
      eq("me@example.com"), 
      eq("Subject"), 
      eq("here should be another body and test shou")
);

// assert that sendMail returned true;

坦率地说，我认为您不需要在这里验证，只需一个 boolean 断言就足够了，但这取决于您。