NullPointerException by testing a Service with mocked JPARepository - spring

Question

I have a ServiceImp where the repository and objectmapper are injected.
When performing the tests I get a nullpointexception.
I believe the Mock is working because when I print the result Candidate createdOne = candidateRepository.save(c1) I get back c1.
#Service
#RequiredArgsConstructor(onConstructor = #__(#Autowired))
public class CandidateServiceImp implements CandidateService {
private final CandidateRepository candidateRepository;
private final ObjectMapper objectMapper;
#Override
public List<CandidateDto> getAllCandidates() {
List<Candidate> candidateList = candidateRepository.findAll();
return candidateList.stream()
.map(Candidate::convertEntityToDto)
.collect(Collectors.toList());
}
#Override
public String findCandidateByIdNormal(Long id) throws JsonProcessingException {
Candidate foundCandidate = candidateRepository.findById(id).orElseThrow(() -> new CandidateNotFoundException(id));
return objectMapper.writerWithView(CandidateViews.Normal.class).writeValueAsString(foundCandidate.convertEntityToDto());
}
#Override
public String findCandidateByIdHr(Long id) throws JsonProcessingException {
Candidate foundCandidate = candidateRepository.findById(id).orElseThrow(() -> new CandidateNotFoundException(id));
return objectMapper.writerWithView(CandidateViews.Hr.class).writeValueAsString(foundCandidate.convertEntityToDto());
}
#Override
public CandidateDto createCandidate(CandidateDto candidateToCreateDto) {
Candidate candidateToCreate = candidateToCreateDto.convertDtoToEntity();
Candidate createdCandidate = candidateRepository.save(candidateToCreate);
return createdCandidate.convertEntityToDto();
}
And this ist my test:
#ExtendWith(SpringExtension.class)
public class CandidateServiceTest {
#InjectMocks
CandidateServiceImp candidateServiceImp;
#Mock
CandidateRepository candidateRepository;
private CandidateDto c1Dto;
private CandidateDto c2Dto;
private List<CandidateDto> candidateDtoList;
private Candidate c1;
private Candidate c2;
private List<Candidate> candidateList;
#BeforeEach
void setUp() {
c1Dto = new CandidateDto("Peter", "Parker", "pp#gmail.com", 3500L);
c2Dto = new CandidateDto("Mary", "Jane", "mj#gmail.com", 4500L);
candidateDtoList = List.of(c1Dto, c2Dto);
c1 = new Candidate("Peter", "Parker", "pp#gmail.com", 3500L);
c2 = new Candidate("Mary", "Jane", "mj#gmail.com", 4500L);
candidateList = List.of(c1, c2);
}
#Test
public void createCandidateShouldReturnCandidateDto() {
Mockito.doReturn(c1).when(candidateRepository).save(c1);
Candidate createdOne = candidateRepository.save(c1);
System.out.println();
System.out.println(createdOne.convertEntityToDto());
System.out.println();
assertEquals(c1Dto, candidateServiceImp.createCandidate(c1Dto));
}
And this is the message :
java.lang.NullPointerException: Cannot invoke "de.evoila.personalAbteilung.models.Candidate.convertEntityToDto()" because "createdCandidate" is null
Could someone tell me why it is not finding the createdCandidate?Thanks =D

Answer 1

As explained in the comments, one solution would be to add #EqualsAndHashCode to candidate.
I also find other solution :
#Test
public void createCandidateShouldReturnCandidateDto() {
Mockito.when(candidateRepository.save(any(Candidate.class))).thenAnswer(AdditionalAnswers.returnsFirstArg());
assertEquals(c1Dto, candidateServiceImp.createCandidate(c1Dto));
}
I mocked the repository with any(Candidate.class) and it also works.