MocMVC giving HttpMessageNotReadableException

An HttpMessageNotReadableException is

Thrown by HttpMessageConverter implementations when the read method fails.

You also get a 400 Bad Request in your response. This should all tell you that you are not sending what your server is expecting. What is your server expecting?

@RequestMapping(value = "/requestpayment", method = RequestMethod.POST, headers="Accept=application/json")
@ResponseBody
public ResponseEntity<PaymentResult> handleRequestPayment(@RequestBody PaymentRequest paymentRequest, HttpServletRequest request, HttpServletResponse response, BindingResult result) throws Exception{

The main thing here is the @RequestBody annotated parameter. So you are telling your server to try and deserialize a PaymentRequest instance from the body of the HTTP POST request.

So let's see the request you are making

mockMvc.perform(post("/requestpayment")
        .contentType(MediaType.APPLICATION_JSON)
        .accept(MediaType.APPLICATION_JSON))
        .andDo(print())
        .andExpect(status().isBadRequest());

I don't see you providing a body to the request. There should be a content(String) call somewhere in there to set the content of the POST request. This content should be a JSON serialization of a PaymentRequest.

Note that because you are using the StandaloneMockMvcBuilder, you might need to set the HttpMessageConverter instances yourself, ie. a MappingJackson2HttpMessageConverter to serialize and deserialize JSON.

---

Note that the BindingResult parameter should come immediately after the parameter to which it's related. Like so

@RequestMapping(value = "/requestpayment", method = RequestMethod.POST, headers="Accept=application/json")
@ResponseBody
public ResponseEntity<PaymentResult> handleRequestPayment(@Valid @RequestBody PaymentRequest paymentRequest, BindingResult result, HttpServletRequest request, HttpServletResponse response) throws Exception{

Don't forget the @Valid.

Note that this

requestPaymentController.setLoginService(mockLoginService);
requestPaymentController.handleRequestPayment(mockPaymentRequest, mockHttpServletRequest, mockHttpServletResponse, mockBindingResult);

is completely unrelated to the MockMvc test you are doing.