MocMVC test for RequestRejectedException giving "Expecting actual not to be null" error

Question

I am trying to add Moc test for below method,

code method:

 @Bean
  public RequestRejectedHandler requestRejectedHandler() {
    return new HttpStatusRequestRejectedHandler();
  }

Moc test code

    @Test
    public void bad_request() throws Exception {
      mockMvc
          .perform(get("//.%252e/.%252e/.%252e/"))
          .andExpect(status().is4xxClientError())
          .andExpect(result -> assertTrue(result.getResolvedException() instanceof RequestRejectedException))
          .andExpect(result -> assertEquals("Bad Request", result.getResolvedException().getMessage()));;
    }
    

It is giving below error

Expecting actual not to be null
java.lang.AssertionError: 
Expecting actual not to be null
    at co.application.controller.ErrorControllerTest$requestError.lambda$bad_request$0(ErrorControllerTest.java:45)
    at org.springframework.test.web.servlet.MockMvc$1.andExpect(MockMvc.java:212)
    at co.application.controller.ErrorControllerTest$requestError.bad_request(ErrorControllerTest.java:44)