spring Junit with Mock return value null

Question

I'm new in JUnit with Mock . This is actual working but I notice receiving null value in TEST using Map<String, Object> The reason for this what if their is condition must not null. Someday I'm going to need this.

What I did was since Map<String, Object> can't be implemented in headers.setAll() because it need Map<String, String> so i convert it.

@RestController
public class TestController {
    
    @GetMapping("/test")
    public String testAuth(@RequestParam String name, @RequestHeader Map<String, Object> head) {
        
        try {
         String conv =  String.valueOf( head.get("head"));
            return name + " "+ conv ;
        } catch (Exception e) {
            return e.getMessage();
        }
    
    
    } 
}

Test

@WebMvcTest(controllers =  TestController.class)
public class ControllerTest {
    
    @Autowired
    private MockMvc mockMvc;
    
    @Test
    public void testControllerHeader() throws Exception {
        
        Map<String, Object> headerMap = new HashMap<String, Object>();
        
          Map<String, String> headObjectToString =  headerMap.entrySet().stream()
        .collect(Collectors.toMap(Map.Entry::getKey, e -> (String)e.getValue()));
          
          HttpHeaders headers = new HttpHeaders();
          headers.setAll(headObjectToString);
          
 
          MvcResult result = mockMvc.perform(MockMvcRequestBuilders
                  .get("/test?name=justin")
                  .headers(headers)
                  .accept(MediaType.APPLICATION_JSON)
                  ).andExpect(status().isOk()).andReturn();


          //i make it error just to see the body
          assertEquals(result.getResponse().getStatus(), 201);
    
         //this the original
        //assertEquals(result.getResponse().getStatus(), 200);
          

        
        
    }

}

Body = justin null

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /test
       Parameters = {name=[justin]}
          Headers = [Accept:"application/json"]
             Body = null
    Session Attrs = {}

Handler:
             Type = com.mock.TestingMokito.Controller.TestController
           Method = com.mock.TestingMokito.Controller.TestController#testAuth(String, Map)

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = null

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 200
    Error message = null
          Headers = [Content-Type:"application/json", Content-Length:"10"]
     Content type = application/json
             Body = justin null
    Forwarded URL = null
   Redirected URL = null
          Cookies = []

Answer 1

You're passing null in the header, that's why it is returning null. In your test class, add some data in the headerMap before converting it to a string.

@WebMvcTest(controllers =  TestController.class)
public class ControllerTest {
    
    @Autowired
    private MockMvc mockMvc;
    
    @Test
    public void testControllerHeader() throws Exception {
        
        Map<String, Object> headerMap = new HashMap<String, Object>();

        headerMap.put("head",new String("This was the bug"));
        
        Map<String, String> headObjectToString =  headerMap.entrySet().stream()
        .collect(Collectors.toMap(Map.Entry::getKey, e -> (String)e.getValue()));
        
        HttpHeaders headers = new HttpHeaders();
        headers.setAll(headObjectToString);
        

        MvcResult result = mockMvc.perform(MockMvcRequestBuilders
                .get("/test?name=justin")
                .headers(headers)
                .accept(MediaType.APPLICATION_JSON)
                ).andExpect(status().isOk()).andReturn();


        //i make it error just to see the body
        assertEquals(result.getResponse().getStatus(), 201);
    
        //this the original
        //assertEquals(result.getResponse().getStatus(), 200);
        

        
        
    }

}