MapStruct mapper not initialized with autowired when debug - spring

Question

I use spring boot 2.3.2 with mapstruct.
In a service class I have a mapper who have an autowired annotation.
#Service
public BillingService{
private BillingRepository billingRepository;
#Autowired
private BillingMapper billingMapper;
#Autowired
public BillingService (BillingRepository billingRepository){
this.billingRepository=billingRepository;
}
public void getBilling(Long billingId){
....
billingMapper.convertTo(...);
}
}
#RunWith(MockitoJUnitRunner.class)
public class BillingServiceTest{
#Mock
BillingRepository billingRepository;
private BillingService bilingService;
#Spy
private BillingMapper billingMapper = Mappers.getMapper(BillingMapper.class);
#BeforeEach
public void setup(){
MockitoAnnotations.initMocks(this);
billingService = new BillingService();
}
#Test
public void testGetBilling(){
List<Billing> billings = new ArrayList<>();
...
List<BillingPayload> payloads = new ArrayList<>();
when(billingMapper.convertTo(billings)).thenReturn(payloads);
bilingService.getBilling(1l);
}
}
#Mapper(componentModel="spring")
public interface BillingMapper{
...
}
When I debug and I'm stuck in getBilling method in BillingService Class, billingMapper is alway null;

Answer 1

You are using very strange configuration. First of all you have method returning BillingService that doesn't specify any return value so this would not even compile. I suggest following way:
#Service
public BillingService{
private final BillingRepository billingRepository;
private final BillingMapper billingMapper;
// constructor with bean injection
public BillingService(final BillingRepository billingRepository,
final BillingMapper billingMapper) {
this.billingRepository = billingRepository;
this.billingMapper = billingMapper;
}
public void getBilling(Long billingId){
....
billingMapper.convertTo(...);
}
}
Then you can configure your test like following:
#RunWith(SpringJUnit4ClassRunner.class)
public class BillingServiceTest {
#Spy private BillingMapper billingMapper = Mappers.getMapper(BillingMapper.class);
#MockBean private BillingRepository billingRepository;
#Autowired private BillingService billingService;
#TestConfiguration
static class BillingServiceTestContextConfiguration {
#Bean public BillingService billingService() {
return new BillingService(billingRepository, billingMapper);
}
}
#Test
public void testGetBilling(){
List<Billing> billings = new ArrayList<>();
...
List<BillingPayload> payloads = new ArrayList<>();
when(billingRepository.findById(1L)).thenReturn(); // someResult
when(billingMapper.convertTo(billings)).thenReturn(payloads);
bilingService.getBilling(1l);
}
}
#Mapper(componentModel="spring")
public interface BillingMapper{
...
}
Similiar configuration should work. Main problem is that you are mixing #Autowired with setter/constructor injection (don't know since your weird method inside BillingService. Also dont know why you use #Spy annotation when you are tryning to Mock interface. #Spy is used to mock actual instance, while #Mock is mocking Class type. I would stick with #MockBean private BillingMapper billingMapper instead if BillingMapper is specified as Bean in your application.