[FIXED] Service in Spring not setting values with Junit

Issue

Im testing my service with Junit but the result is not the expected. When i save my entity, the return date is not setted in service.

Test:

@Test
@DisplayName("Should set determined time for return date")
public void shouldSetReturnDate() {

    ClientDTORequest dto = createNewDTOClient();
    Client client = createNewClient();

    Mockito.when(clientRepository.save(Mockito.any())).thenReturn(client);
    Client saved = clientService.save(dto);

    Assertions.assertEquals(dateTimeNow.plusMinutes(30), saved.getReturnDate());
}

My createNewClient():

private Client createNewClient() {
    //the null param is the return date
    return new Client(1L, "name", null);
}

My service:

    public Client save(ClientDTORequest dto) {

        Client client = mapper.map(dto, Client.class);
        client.setReturnDate(dateTimeNow.plusMinutes(30));
        Client savedClient = clientRepository.save(client);

        return savedClient;
    }

And when the test result:

org.opentest4j.AssertionFailedError: 
Expected :2022-04-04T01:17:25.715895900
Actual   :null

The result is not passed by the service to mock, this is my shot, but i dont know why.

Thanks!

Solution

After some hours of testing i found the problem:

My service was changing data, but was overridden by my mock:

Mockito.when(clientRepository.save(Mockito.any())).thenReturn(client); <-- mock overridden the changed data from service
Client saved = clientService.save(dto);

So i found ArgumentCaptor, where i can get the object from method call:

Declaring the Captor:

@Captor
ArgumentCaptor<Client> clientCaptor;

Using at test method:

Mockito.when(clientRepository.save(clientCaptor.capture())).thenReturn(client); //<-- capturing the result
clientService.save(dto);
Client saved = clientCaptor.getValue() //getting object

Assertions.assertEquals(dto.getReturnDate().plusMinutes(30), saved.getReturnDate()); //assertion

Answered By - devs4wl
Answer Checked By - Katrina (JavaFixing Volunteer)