如何测试我的servlet是否调用了某些方法？

Question

I have a servlet:

class MyServlet extends HttpServlet
{
   public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
   {
       String one = request.getParameter("one");
       String two = request.getParameter("two");
       addNew(one, two);
   }

   public void addNew(String one, String two){
        // DAO called here to insert a new record
   }

}

I want to test if 'addNew' is called without executing its body. I know that I need a Test Double, but don't know if a spy is the best way. I thought in doing this:

class MyServletSpy extends MyServlet
{
   private boolean addNewGotCalled = false;

   @Override
   public void addNew(String one, Integer, two)
   {
       addNewGotCalled = true;
   }

   public boolean addNewWasCalled()
   {
       return this.addNewGotCalled;
   }
}

Is this the right way? I feel that extending MyServlet is a litle strange, it seems that I am allowing my test to have a dependency.

Answer 1

Quite hard to understand what you really want to test but you can try to take a look at Jetty if you want to test the behaviour of your Servlet : https://webtide.com/unit-test-servlets-with-jetty/

EDIT

Thanks for your clarification. In your case, one solution is to use Mockito.spy to test that the addNew method is successfully called.

First you need the mockito dependency:

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-all</artifactId>
    <version>1.9.5</version>
    <scope>test</scope>
</dependency>

Then you can use spy method to test your Servlet :

/**
 * Test of {@link MyServlet} class
 * @author rouliboy
 */
public class MyServletTest
{
   @Test
   public void testAddNewCall() throws ServletException, IOException
   {
      // Initialization
      MyServlet myServlet = new MyServlet();
      myServlet = Mockito.spy(myServlet);

      final HttpServletRequest mockHttpServletRequest = Mockito.mock(HttpServletRequest.class);
      final HttpServletResponse mockHttpServletResponse = Mockito.mock(HttpServletResponse.class);

      Mockito.when(mockHttpServletRequest.getParameter("one")).thenReturn("oneReturn");
      Mockito.when(mockHttpServletRequest.getParameter("two")).thenReturn("twoReturn");

      // Test
      myServlet.doPost(mockHttpServletRequest, mockHttpServletResponse);

      // Verification
      Mockito.verify(myServlet).addNew("oneReturn", "twoReturn");
   }
} 

EXPLANATION

First we spy the Servlet using:

myServlet = Mockito.spy(myServlet);

Using spy , we can check which methods are called in the Servlet.

Then we mock the HttpServletRequest and HttpServletResponse inputs of doPost method. Using mocks, we can define the behaviour of return values by HttpServletRequest.getParameter(...) :

Mockito.when(mockHttpServletRequest.getParameter("one")).thenReturn("oneReturn");
Mockito.when(mockHttpServletRequest.getParameter("two")).thenReturn("twoReturn");

And after calling doPost method, we verify that addNew is successfully called :

Mockito.verify(myServlet).addNew("oneReturn", "twoReturn");

However, I think that it would be better to test fully your Servlet (for example using Jetty and mocking your DAO) instead of just testing if your addNew method is called.