public void testWithPrefix() throws Exception {
   UrlFilenameViewController ctrl = new UrlFilenameViewController();
   ctrl.setPrefix("mypre_");
   MockHttpServletRequest request = new MockHttpServletRequest("GET", "/index.html");
   MockHttpServletResponse response = new MockHttpServletResponse();
   ModelAndView mv = ctrl.handleRequest(request, response);
   assertEquals("mypre_index", mv.getViewName());
   assertTrue(mv.getModel().isEmpty());
 }
 public void testSettingPrefixToNullCausesEmptyStringToBeUsed() throws Exception {
   UrlFilenameViewController ctrl = new UrlFilenameViewController();
   ctrl.setPrefix(null);
   assertNotNull(
       "When setPrefix(..) is called with a null argument, the empty string value must be used instead.",
       ctrl.getPrefix());
   assertEquals(
       "When setPrefix(..) is called with a null argument, the empty string value must be used instead.",
       "",
       ctrl.getPrefix());
 }