final StringWriter stringWriter = new StringWriter();
final PrintWriter printWriter = new PrintWriter(stringWriter);
when(response.getWriter()).thenReturn(printWriter);
when(request.getMethod()).thenReturn(RequestMethod.GET.toString());
ErrorResponseImpl errorResponse = new ErrorResponseImpl(HttpServletResponse.SC_NOT_FOUND, new Exception("not found"));
new JsonResponder().respond(errorResponse, routeContext);
verify(response).getWriter();
verify(response).setCharacterEncoding("UTF-8");
final ObjectMapper mapper = new ObjectMapper();
final Map readValue = mapper.readValue(stringWriter.toString(), Map.class);