Mockito：注入的模拟类不注入其他类

Question

So I have a simple java class:

@Component
public class IWantToTestThisClass {

@Autowired
private ClassA classA;

@Autowired 
private ClassB classB;

public ObjectA doIt(...) {
   classB.returnObject();
}

ClassA contains:

@Component
public class ClassA { 

@Autowired 
private ClassB classB;

public ObjectA doIt() {
   classB.returnObject(...);
}

ClassB:

@Component
public class ClassB { 

public ObjectA returnObject(...) {
   ...
}

My test setup looks like this:

@InjectMocks
private IWantToTestThisClass iWantToTestThisClass;

@Mock
private ClassA classA;

@Mock
private ClassB classB;

@Before
public void setUp() {
    initMocks(this);

    when(classA.doSmt()).thenCallRealMethod();
    when(classB.doSmt()).thenCallRealMethod();
}

The problem is that ClassB is not injected for ClassA.

Then returnObject(ClassB) is called through classA it returns NullPointerException(ClassB is not mocked/injected).

If returnObject(classB) is called through IWantToTestThisClass it is okay.

Is it a way to inject ClassB for both classes at the same time? I want to call real methods, not mocked ones.

Answer 1

You 're injecting mock into IWantToTestThisClass, and not into ClassA. So there is no mock into ClassA and B isn't injected there.

Try to add @InjectMocks before classA

Or you can do :

ClassB mB = Mockito.mock(ClassB.class);
classA.setClassB(mB);

if you add the setter setClassB(...) to ClassA

Answer 2

An @Autowired can be replaced by constructor inject. So, your classA will be:

@Component
public class ClassA { 

    private static ClassB classB;

    public ClassA(ClassB classB){
        this.classB=classB;
    }

    public ObjectA doIt() {
       classB.returnObject(...);
    }
}

By this way you can inject the classB mock later in you @Before setUp method:

@Before
public void setUp() {
    initMocks(this);
    when(classA.doSmt()).thenCallRealMethod();
    when(classB.doSmt()).thenCallRealMethod();
    classB = new classB(classA);
}