Mocking MapperFacade return in Spring Boot Test with Mockito

I haven't seen this particular question answered in a way that's resolving my issue.

I have a service class that is constructed with a repository and an Orika MapperFacade. In testing, I'm arranging a list of Entities returned by the repository call. my doReturn(testList).when(testRepository).findAllBy... seems to be working. My actual result list contains the same amount of elements (.size()) I've specified in my mocked list, however the values are all null. I'm fairly new to Spring Boot, and definitely new to Mockito. I'm currently using a bean that returns a MapperFacade created with a MapperFactory and has several class maps defined. Right now I'm using a @Spy for my MapperFacade in test, and can pass based strictly on asserting that the size of the lists is the same. I understand it might be that I need to @Mock the behavior or the MapperFacade instead, although it's being used to iterate over a list in the service class. Not positive how to implement that in test. I could build another list of DTO's that would generally be returned from a loop iterating through the entities, but I'm new to Mockito grammar and not sure how I'd run that return.

I get a NullPointerException when trying to log or assert on a .getAnyValue from an element of the list, but the size of the list changes when I add or remove elements in the arranged list.

Any info appreciated.

Service class

public class FightService {
    private FightRepository repository;
    private MapperFacade mapper;

    @Autowired
    public FightService(FightRepository r, MapperFacade m) {
        this.repository = r;
        this.mapper = m;


    }

    public List<FightDTO> getFightsByWinRound(int winRound){

        List<FightEntity> entities = repository.findAllByWinRound(winRound);
        List<FightDTO> returnVal = new ArrayList<>();
        for(FightEntity e: entities){
            FightDTO dto = mapper.map(e, FightDTO.class);
            returnVal.add(dto);
        }
        return returnVal;
    }
}

Service Test

@Slf4j
@RunWith(MockitoJUnitRunner.class)
public class FightServiceTest{

    @Spy
    private MapperFacade mapperFacade;

    @Mock
    private FightRepository testRepository;

    @InjectMocks
    private FightService systemUnderTest;




    @Test
    public void testGetFightsByWinRound_ScenarioA() throws Exception{
        //Arrange

        List<FightEntity> testList = new ArrayList<>();
        FightEntity fightA = new FightEntity();
        fightA.setFighter1("A");
        fightA.setWinRound(15);
        testList.add(fightA);
        FightEntity fightB = new FightEntity();
        fightB.setFighter1("B");
        fightB.setWinRound(15);
        testList.add(fightB);
        FightEntity fightC = new FightEntity();
        fightC.setFighter1("C");
        fightC.setWinRound(15);
        testList.add(fightC);

        doReturn(testList).when(testRepository).findAllByWinRound(15);

        

        //Act

        List<FightDTO> actual = systemUnderTest.getFightsByWinRound(15);


        //Assert

        Assert.assertThat(actual.size(), is(3));
        // I would be adding Assert.assertThat(actual.get(0).getFighter1(), is("A")) , but this is where the NPE arises.
    


        //Verify
    }
}

This worked for

@InjectMocks
private ServiceClass serviceClass;

@Before
public void setUp() {
    MockitoAnnotations.initMocks(this);
    factory = new DefaultMapperFactory.Builder().build();
    when(mapper.getMapperFacade()).thenReturn(factory.getMapperFacade());
    // In case of custom mapping
    factory.classMap(Source.class, Dest.class).customize(new CustomMapper())
            .byDefault().register();
}

You can check some internal tests at https://github.com/elaatifi/orika/blob/master/tests/src/main/java/ma/glasnost/orika/test/converter/NumericConvertersTestCase.java#L113