如何通过MockMvc测试ModelAttribute参数

Question

I wrote this controller method:

  @RequestMapping("/submitFormAdd")
        public ModelAndView submitFormAdd(
                Model model,
                @ModelAttribute("myCandidate") @Valid Candidate myCandidate,
                BindingResult result,
                RedirectAttributes redirectAttributes) {
            if (result.hasErrors()) {
                return new ModelAndView("candidateDetailsAdd");
            }

            myCandidate.setDate(new Date());
            candidateService.add(myCandidate);

            redirectAttributes.addAttribute("message", "added Correctly at "+ new Date() );
            redirectAttributes.addAttribute("id", myCandidate.getId());
            ModelAndView modelAndView = new ModelAndView(
                    "redirect:loadCandidateById");
            return modelAndView;
        }

UPDATE

myCandidate instantiants so:

@ModelAttribute(value = "myCandidate")
    public Candidate loadCandidateById(
            @RequestParam(required = false) Integer candidateId) {
        if (candidateId != null)
            return candidateService.findById(candidateId);
        return null;
    }

What way can I test that this method gets Candidate ?

I use MockMvc.

Answer 1

You cannot test specifically that the method will receive the Candidate argument. Your options are to either send bad request data and therefore make Spring unable to correctly instantiate it and return a 400 error (but that can happen for other reasons). Or send correct data and receive what you normally expect.

Note that you shouldn't be testing Spring functionality. When you use a 3rd party framework, you assume that it has been tested properly, especially one like Spring.