code: @Test public void test() throws Exception {
    DubboSwaggerApiListingResource resource=new DubboSwaggerApiListingResource();
    app=mock(Application.class);
    sc=mock(ServletConfig.class);
    Set<Class<?>> sets=new HashSet<Class<?>>();
    sets.add(SwaggerService.class);
    when(sc.getServletContext()).thenReturn(mock(ServletContext.class));
    when(app.getClasses()).thenReturn(sets);
    Response response=resource.getListingJson(app,sc,null,new ResteasyUriInfo(new URI("http://rest.test")));
    Assert.assertNotNull(response);
    Swagger swagger=(Swagger)response.getEntity();
    Assert.assertEquals("SwaggerService",swagger.getTags().get(0).getName());
    Assert.assertEquals("/demoService/hello",swagger.getPaths().keySet().toArray()[0].toString());
  }
  