How to unit test a ResponseBody or ResponseEntity sent by a spring mvc Controller?

Question

When I do junit tests, I do something like this to test spring mvc controllers :

request.setRequestURI("/projects/"+idProject+"/modify");
ModelAndView mv = handlerAdapter.handle(request, response, controller);

where controller tested is like :

@RequestMapping(value = "{id}/modify")
public String content(ModelMap model, @PathVariable("id") Project object) {

But I don't find how to get the ResponseBody answer of request handlers defined like this :

@RequestMapping("/management/search")
public @ResponseBody ArrayList<SearchData> search(@RequestParam("q")) {
        ....
                ....
        ArrayList<SearchData> datas = ....;

        return datas;
    }

Solution

Your unit test only needs to verify the contents of the return value of the method:

ArrayList<SearchData> results = controller.search("value");
assertThat(results, ...)

The @ResponseBody annotation is irrelevant. This is one of the big benefits of annotated controllers - your unit tests can focus on the business logic, not the framework mechanics. With pre-annotation controllers, half of your test code is spent constructing mock requests, responses, and associated gubbins like that. It's a distraction.

Testing that your code's annotations integrate properly with the framework is the job of integration and/or functional tests.