Mock bean is autowired into #Spy bean mockito - spring

Question

My unit test try #Spy beanA. But BeanA #autowire bean B as bellow:
#RunWith(SpringRunner.class)
public class MyServiceImplTest {
#Spy
private BeanA beanA;
#InjectMocks
private MyService myService = new MyServiceImpl();
#Test
public void testDoSomeThing(){
myService.doSomeThing();
}
}
MyServiceImpl as bellow :
#Service
public class MyServiceImpl {
#Autowired
private BeanA beanA;
public doSomeThing(){
....
beanA.beanADoSomeThing()
....
}
}
beanA as bellow
#Service
public class BeanA {
#Autowired
private BeanB beanB;
public beanADoSomeThing(){
...
//Null pointer exception in here because beanB=null
beanB.beanBDoSomeThing()
}
}
when run unit test i get null pointer exception at line beanB.beanBDoSomeThing(), I can understand the reason but how to resolve this issue?
I have tried
#Mock
private BeanB beanB;
But this not work, how to resolve this issue ?

Answer 1

If you want to spy your bean in context, you need #SpyBean annotation instead of #Spy and also you should autowire your service to be tested, smth like this:
#SpringBootTest
#RunWith(SpringRunner.class)
public class ExTest {
#SpyBean
private BeanA beanA;
#Autowired
private MyService myService;
#Test
public void testDoSomeThing() {
myService.doSomeThing();
}
}
If you don't want to load application context and test only MyServiceImpl behavior in isolation, you can use pure Mockito and mock or spy dependencies of MyServiceImpl:
#RunWith(MockitoJUnitRunner.class)
public class MockitTest {
#InjectMocks
private MyServiceImpl myService;
#Mock
private BeanA beanA;
#Test(expected = RuntimeException.class)
public void test() {
doThrow(new RuntimeException()).when(beanA).beanADoSomeThing();
myService.doSomeThing();
}
}