### Question:
AppUtils { public String getMessage(final String messageKey) { return messageSource.getMessage(messageKey, null, LocaleContextHolder.getLocale()); }  List<String> getModelErrors(final BindingResult bindingResult, final String... excludedFields); void setCurrentPage(final Model model, final String currentPage); @SuppressWarnings("unchecked") void addNotification(final RedirectAttributes redirectAttributes, final Notification notification); List<String> getUnexpectedErrorMessageAsList(); String getUnexpectedErrorMessage(); List<String> getMessages(final String... messageKeys); String getMessage(final String messageKey); String getReturnUrl(final String url, final String fallback); String getLocalUrl(final HttpServletRequest request);  }### Answer:
@Test public void test_getMessage_success() { when(messageSource.getMessage("test message", null, Locale.ENGLISH)).thenReturn("test message result"); final String result = appUtils.getMessage("test message"); assertEquals("test message result", result); }