Mockito servlet test: cannot use response - it's not committed

I've made a basic test for servlet to test it's response status code, but it doesn't work - it's always 0, although I've set the response status code inside the servlet to 200.

public class TestMyServlet extends Mockito {

@Test
public void test() throws Exception {
    HttpServletRequest request = mock(HttpServletRequest.class);
    HttpServletResponse response = mock(HttpServletResponse.class);

    when(request.getParameter("test")).thenReturn("1");

    new MyServlet().doPost(request, response);

    System.out.println(response.isCommited()); // false
    System.out.println(response.getContentType()); // null
    System.out.println(response.getStatus()); // 0
  }
}

How to let this work?