java - 如何在 testet 方法中编写带有断言的单元测试？

Question

我有一个问题，我喜欢在我的 junit 测试中测试一些被另一种方法隐藏的值。你怎么会这样的事情。与莫基托？子类化？

这里的问题:

public class MyService extends AbstractService {

 public ResponseObject insert(SomeData data) {
     Request request = createRequest(data);
     Response response = new Response();
     callService(request, response);
     return createResponseObject(response);
 }

 protected void callBackendService(...) {
     ...
 }
}

您将如何测试传递给

的值

callBackendService()

method?

Is there a more elegant way than use subclassing?

 MyService service = new MyService() {

   @Override
   protected void callBackendService(...) {
      assertEquals(...);
      ...
   }
 }

问候，

迈克

Answer 1

一种观点认为，您应该只对公共(public)类(class)进行单元测试。因此，只需对从 insert() 返回的 ResponseObject 进行断言。

否则，使用像 Mockito 这样的模拟框架，您可以将 callBackendService() 方法分解到它自己的类中(例如 ServiceCaller)。然后您可以创建一个模拟 ServiceCaller 对象并验证传递给它的参数。

像这样的……

public class ServiceCaller  {

    public callBackendService(Request request, Response response) {
        ...
    }

}

那么你的类应该看起来像这样......

public class MyService extends AbstractService {


    private ServiceCaller serviceCaller;

    public ResponseObject insert(SomeData data) {
     Request request = createRequest(data);
     Response response = new Response();
     serviceCaller.callBackendService(request, response);
     return createResponseObject(response);
    }

    public setServiceCaller(ServiceCaller caller) {
        this.serviceCaller = caller;        
    }

}

最后 Mockito 测试是这样的......

@Test
public void testInsert() throws Exception {

    // object to test
    MyService ms = new MyService();

    // test input values
    Request req = new Request();

    Response resp = new Response();

    // create a mock class and inject it into your test class
    ServiceCaller sc = mock(ServiceCaller.class);

    ms.setServiceCaller = sc;

    // execute the method under test
    ms.insert(req, resp);

    // now you can see if your mock was called with the expected params
    verify(sc).callBackendService(req, resp);
}

为简洁起见，我省略了使用接口(interface)等进行的良好设计，但您会明白这一点。