Cara memeriksa nilai di isi respons dengan mockMvc - AssertionError: Status yang diharapkan:‹201› tetapi:‹400›

Saya baru dalam tes penulisan dan saya mencoba menulis tes junit untuk kelas pengontrol saya menggunakan mockMvc.

Inilah kelas saya:

public class StudentDTO {

private final String firstName;
private final String lastName;
private final String JMBAG;
private final Integer numberOfECTS;
private final boolean tuitionShouldBePaid;}

Kelas komando

public class StudentCommand { 
@NotBlank (message = "First name must not be empty!")
private String firstName;

@NotBlank (message = "Last name must not be empty!")
private String lastName;


@NotNull(message = "Date of birth must be entered!")
@Past(message = "Date of birth must be in the past!")
private LocalDate dateOfBirth;

@NotBlank(message = "JMBAG must not be empty!")
@Pattern(message = "JMBAG must have 10 digits", regexp = "[\\d]{10}")
private String jmbag;

@NotNull(message = "Number of ECTS points must be entered!")
@PositiveOrZero(message = "Number of ECTS points must be entered as a positive integer!")
private Integer numberOfECTS;}

Kelas pengontrol:

@Secured({"ROLE_ADMIN"})
@PostMapping
public ResponseEntity<StudentDTO> save(@Valid @RequestBody final StudentCommand command){
    return studentService.save(command)
            .map(
                    studentDTO -> ResponseEntity
                            .status(HttpStatus.CREATED)
                            .body(studentDTO)
            )
            .orElseGet(
                    () -> ResponseEntity
                            .status(HttpStatus.CONFLICT)
                            .build()
            );
}

Kelas tes:

@SpringBootTest
@AutoConfigureMockMvc class StudentControllerTest {
@Autowired
private MockMvc mockMvc;

@MockBean
private StudentService studentServiceMock;

@Autowired
private ObjectMapper objectMapper;

private final String TEST_FIRST_NAME = "Marry";
private final String TEST_LAST_NAME = "Blinks";
private final String TEST_JMBAG = "0025478451";
private final Integer TEST_NUMBER_OF_ECTS = 55;
private final boolean TEST_TUITION_SHOULD_BE_PAID = true;
private final LocalDate TEST_DATE_OF_BIRTH = LocalDate.parse("1999-01-12");

@Test
void testSave() throws Exception {

    StudentCommand studentCommand = new StudentCommand(TEST_FIRST_NAME,TEST_LAST_NAME,TEST_DATE_OF_BIRTH,TEST_JMBAG,TEST_NUMBER_OF_ECTS);

    this.mockMvc.perform(
            post("/student")
                    .with(user("admin")
                            .password("test")
                            .roles("ADMIN")
                    )
                    .with(csrf())
            .contentType(MediaType.APPLICATION_JSON)
            .content(objectMapper.writeValueAsString(studentCommand))
            .accept(MediaType.APPLICATION_JSON)
    )
            .andExpect(status().isCreated())
            .andExpect(content().contentType(MediaType.APPLICATION_JSON))
            .andExpect(jsonPath("$.jmbag").value(TEST_JMBAG))
            .andExpect(jsonPath("$.firstName").value(TEST_FIRST_NAME))
            .andExpect(jsonPath("$.lastName").value(TEST_LAST_NAME));
}

Saya selalu mendapatkan tes gagal dengan kesalahan ini:

MockHttpServletRequest:
      HTTP Method = POST
      Request URI = /student
       Parameters = {_csrf=[30de7a8f-a3d5-429d-a778-beabd1a533da]}
          Headers = [Content-Type:"application/json;charset=UTF-8", Accept:"application/json", Content-Length:"272"]
             Body = {"firstName":"Marry","lastName":"Blinks","dateOfBirth":{"year":1999,"month":"JANUARY","monthValue":1,"dayOfMonth":12,"chronology":{"id":"ISO","calendarType":"iso8601"},"dayOfWeek":"TUESDAY","leapYear":false,"dayOfYear":12,"era":"CE"},"jmbag":"0025478451","numberOfECTS":55}
    Session Attrs = {}
Handler:
             Type = com.studapp.students.StudentController
           Method = com.studapp.students.StudentController#save(StudentCommand)
MockHttpServletResponse:
           Status = 400
    Error message = null
          Headers = [Vary:"Origin", "Access-Control-Request-Method", "Access-Control-Request-Headers", X-Content-Type-Options:"nosniff", X-XSS-Protection:"1; mode=block", Cache-Control:"no-cache, no-store, max-age=0, must-revalidate", Pragma:"no-cache", Expires:"0", X-Frame-Options:"DENY"]
     Content type = null
             Body = 
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
java.lang.AssertionError: Status expected:<201> but was:<400>
Expected :201
Actual   :400

Saya tidak yakin mengapa itu gagal. Mengapa isi respons kosong? Saya tidak ingin memanggil layanan saya karena saya tidak mengujinya, tetapi saya merasa harus memanggilnya entah bagaimana caranya (tetapi sekali lagi, saya tidak menguji layanan tersebut). Setiap saran akan dihargai.