Spring Test Mock single field / Constructor injection

Let say we have

@Component
public class MyService {

    private ServiceA serviceA;
    private ServiceB serviceB;

    @Autowired
    public MyService(ServiceA serviceA, ServiceB serviceB) {
        this.serviceA = serviceA;
        this.serviceB = serviceB;
    }

}

@Component
public class ServiceA {
    private ServiceC serviceC;

    @Autowired
    public ServiceA(ServiceC serviceC) {
        this.serviceC = serviceC;
    }
}

@Component
public class ServiceB {

    @Autowired
    private ServiceE serviceE;
}

Then I have my Groovy/Spock test:

@ContextConfiguration(
        loader = SpringApplicationContextLoader,
        classes = ManagementApplication.class
)
@WebAppConfiguration
class MyTest extends Specification {

    @InjectMock
    private MyService myService

    @Mock
    private ServiceA serviceA

    def setup() {
        MockitoAnnotations.initMocks(this)
    }

}

So as you can see MyService injects ServiceA and ServiceB with constructor injection. ServiceA also uses constructor injection while ServiceB uses field injection. In my test I want to mock ServiceA but to Autowire ServiceB. However ServiceA seems to be injected normally (not mocked). Which is the appropriate way to do this?