Unit testing using jUnit5 and mockito - spring

Question

Hi Im having troubles with my saveStudent method I can't seem to make the test work. What my saveStudent method do is when I add a student it automatically adds the fixed subjects from the database to the student. Can anyone explain to me what Im doing wrong in the testing and how to test this kind of method. Gladly appreciate it. Thank you for the answer!
Here is my TestService and my ServiceImplimentation
#ExtendWith(MockitoExtension.class)
public class StudentServiceTest {
#Mock
private StudentRepository studentRepository;
#Mock
private SubjectRepository subjectRepository;
#InjectMocks
private StudentServiceImpl studentService;
private Student student;
private List<Subject> subject;
// private List<Subject> subjectList;
private Collection<Remark> remarks = new ArrayList<>();
#BeforeEach
public void setup() {
student = new Student(1L, "Martin", 6, remarks);
subject = Arrays.asList(
new Subject(1L, "Math", remarks),
new Subject(2L, "English", remarks));
}
// JUnit test for saveStudent method
#DisplayName("JUnit test for saveStudent method")
#Test
public void givenStudentObject_whenSaveStudent_thenReturnStudentObject() {
given(subjectRepository.findAll()).willReturn(subject);
System.out.println(subject);
given(studentRepository.save(student)).willReturn(student);
System.out.println(studentRepository);
System.out.println(studentService);
Student savedStudent = studentService.saveStudent(student);
System.out.println(savedStudent);
assertThat(savedStudent).isNotNull();
}
// JUnit test for getStudentList method
#DisplayName("JUnit test for getStudentList method")
#Test
public void givenStudentsList_whenGetAllStudents_thenReturnStudentsList() {
Student student1 = new Student(1L, "Edmark", 4, remarks);
given(studentRepository.findAll()).willReturn(Arrays.asList(student, student1));
List<Student> studentList = studentService.findAll();
assertThat(studentList).isNotNull();
assertThat(studentList.size()).isEqualTo(2);
}
// JUnit test for getStudentById method
#DisplayName("JUnit test for getStudentById method")
#Test
public void givenStudentId_whenGetStudentId_thenReturnStudentObject() {
given(studentRepository.findById(1L)).willReturn(Optional.of(student));
Student savedStudent = studentService.findById(student.getStudentId());
assertThat(savedStudent).isNotNull();
}
// JUnit test for updateStudent method
#DisplayName("JUnit test for updateStudent method")
#Test
public void givenStudentObject_whenUpdateStudent_thenReturnUpdatedStudent() {
given(studentRepository.findById(1L)).willReturn(Optional.of(student));
given(studentRepository.save(student)).willReturn(student);
student.setStudentGrade(8);
student.setStudentName("Mark");
Student updatedStudent = studentService.updateStudent(1L, student);
assertThat(updatedStudent.getStudentName()).isEqualTo("Mark");
assertThat(updatedStudent.getStudentGrade()).isEqualTo(8);
}
#DisplayName("JUnit test for deleteStudent method")
#Test
public void givenStudentId_whenDeleteStudent_thenNothing() {
long studentId = 1L;
given(studentRepository.findById(studentId)).willReturn(Optional.of(student));
BDDMockito.willDoNothing().given(studentRepository).deleteById(studentId);
studentService.deleteStudent(studentId);
verify(studentRepository, times(1)).deleteById(studentId);
}
}
#Service
public class StudentServiceImpl implements StudentService {
#Autowired
private SubjectRepository subjectRepository;
private StudentRepository studentRepository;
public StudentServiceImpl(StudentRepository studentRepository) {
this.studentRepository = studentRepository;
}
#Override
public Student saveStudent(Student student) {
Collection<Remark> remarkList = new ArrayList<>();
List<Subject> subjects = subjectRepository.findAll();
for (Subject subject : subjects) {
Remark remark = new Remark();
remark.setSubject(subject);
remark.setStudent(student);
remark.setGrade(0);
remarkList.add(remark);
}
student.setRemarks(remarkList);
return studentRepository.save(student);
}
#Override
public List<Student> findAll() {
return studentRepository.findAll();
}
#Override
public Student findById(Long studentId) {
Optional<Student> student = studentRepository.findById(studentId);
if (!student.isPresent()) {
throw new ResourceNotFoundException("Student not found with id : " + studentId);
}
return studentRepository.findById(studentId).get();
}
#Override
public Student updateStudent(#PathVariable(value = "id") Long studentId, #RequestBody Student student) {
Optional<Student> tempStudent = studentRepository.findById(studentId);
if (!tempStudent.isPresent()) {
throw new ResourceNotFoundException("Student not found with id : " + studentId);
}
Student studentDetails = tempStudent.get();
studentDetails.setStudentName(student.getStudentName());
studentDetails.setStudentGrade(student.getStudentGrade());
studentDetails.getRemarks().addAll(student.getRemarks());
Student updatedStudent = studentRepository.save(studentDetails);
return updatedStudent;
}
#Override
public void deleteStudent(long studentId) {
Optional<Student> student = studentRepository.findById(studentId);
if (!student.isPresent()) {
throw new ResourceNotFoundException("Student not found with id : " + studentId +" or already deleted");
}
studentRepository.deleteById(studentId);
}
}