Mockito预计会出现异常

Question

我正在尝试用Mockito和Junit测试下面的方法：

@Transactional
@RequestMapping(method=RequestMethod.PUT,value ="/updateEmployer/{empId}")
public @ResponseBody Object updateEmployer(@PathVariable Integer empId,) throws Exception {
    Employee e = EmployeeRepository.findOne(empId);
    for (Department de : e.getDepartement()){
        de.setDepartmentName(e.getName + "_" + de.getName());       
    }
    EmployeeRepository..saveAndFlush(e);
    return null;
}   

这是测试方法：

@Test  // throw java.lang.NullPointerException
 public void updateEmployeeFailureTest() throws Exception {
        mockMvc.perform(
            MockMvcRequestBuilders
                    .put("/updateEmployer/{empId}",18)                      
                    .accept(MediaType.APPLICATION_JSON)).andDo(print())         
              .andExpect(MockMvcResultMatchers.view().name("errorPage"))
               .andExpect(MockMvcResultMatchers.model().attributeExists("exception"))
              .andExpect(MockMvcResultMatchers.forwardedUrl("/WEB-INF/jsp/errorPage.jsp"))
              .andExpect(MockMvcResultMatchers.status().isInternalServerError());       
    }   

打印堆栈：

 MockHttpServletRequest:
     HTTP Method = PUT
     Request URI = /updateEmployer/18
      Parameters = {}
         Headers = {Content-Type=[application/json], Accept=   application/json]}
         Handler:
            Type = com.controllers.employeeController
          Method = public java.lang.Object    com.controllers.employeeController.updateEmployer(java.lang.Integer) throws   java.lang.Exception
           Async:
      Was async started = false
      Async result = null
    Resolved Exception:
            ***Type = java.lang.NullPointerException***
    ModelAndView:
       View name = errorPage
            View = null
       Attribute = exception
           ***value = java.lang.NullPointerException***
         FlashMap:
  MockHttpServletResponse:
          Status = 500
   Error message = null
         Headers = {}
    Content type = null
            Body = 
   Forwarded URL = /WEB-INF/jsp/errorPage.jsp
  Redirected URL = null
         Cookies = []

这是有效的，但当我试图捕捉此方法抛出的文本或异常时
添加@Test（应为java.lang.NullPointerException.class）时，我出现了以下错误：

java.lang.AssertionError:预期异常：java.lang.NullPointerException

当我试图将nullPointerException Text作为ModelAndView部分的属性（exception）的值时，我得到了以下错误：

java.lang.AssertionError:应为模型属性"exception"：java.lang.NullPointerException，但实际为：java.lang.NullPointerException

有没有一种方法可以使用mockito（mockmvc）来期待抛出的异常或值attribut中的文本（值=java.lang.NullPointerException）或Resolved exception部分中的文本？

任何帮助都将不胜感激

Answer 1

您需要测试模型的exception属性是否是NullPointerException的实例。

这可以使用Hamcrest匹配器完成：

 .andExpect(MockMvcResultMatchers.model().attribute(
     "exception", 
      Matchers.isA(NullPointerException.class))

Answer 2

一个更简单的解决方案是通过MvcResult捕获exception，如下所示：

...
MvcResult result = mockMvc.perform(...)
        ...
        ...
        .andReturn();
assertThat(result.getResolvedException(), instanceOf(YourException.class));
assertThat(result.getResolvedException().getMessage(), is("Your exception message");
...