CriteriaQuery return nullpointerexception mockito

Question

I'm starting my test using mockito. first of all i need to test .findAll() that is a CriteriaQuery...

UserFacade extends AbstractFacade which have this findAll .

public abstract class AbstractFacade<T> {

    private Class<T> entityClass;

    public AbstractFacade(Class<T> entityClass) {
        this.entityClass = entityClass;
    }

    protected abstract EntityManager getEntityManager();

    ....

    public List<T> findAll() {
        CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
        CriteriaQuery<T> cq = cb.createQuery(entityClass);
        Root<T> rootEntry = cq.from(entityClass);
        CriteriaQuery<T> all = cq.select(rootEntry);
        TypedQuery<T> allQuery = em.createQuery(all);
        return allQuery.getResultList();
    }
    ...

My test:

@RunWith(MockitoJUnitRunner.class)
public class UserFacadeTest {

    public UserFacadeTest() {
    }
    @Mock
    private EntityManager mockedEM;
    @Mock
    private CriteriaQuery mockedCQ;
    @Mock
    private CriteriaQuery mockedCQAll;    
    @Mock
    private Root mockedRoot;
    @Mock
    private CriteriaBuilder mockedCB;
    @Mock
    private TypedQuery mockedTQ;
    private UserFacade userFacade;
    List<User> userList= new ArrayList<>();

    @Before
    public void setUp() {
        userFacade=new UserFacade();
        userFacade.setEm(mockedEM);
        when(mockedEM.getCriteriaBuilder()).thenReturn(mockedCB);
        when(mockedCB.createQuery()).thenReturn(mockedCQ);
        when(mockedCQ.from(User.class)).thenReturn(mockedRoot);
        when(mockedCQ.select(mockedRoot)).thenReturn(mockedCQAll);
        when(mockedEM.createQuery(mockedCQAll)).thenReturn(mockedTQ);
        when(mockedTQ.getResultList()).thenReturn(userList);
    }

    @Test
    public void testFindAll() {
        System.out.println("findAll");
        User user = new User(1, "username", "password", "email", new Date());
        userFacade.create(user);
        verify(mockedEM, times(1)).persist(any());
        userList.add(user);
        //next line cause NullPointerException
        List list=userFacade.findAll();

        assertTrue("Should return 1", 1==list.size());

    }

debugging my test i saw this:

    ....

    public List<T> findAll() {
        CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
        CriteriaQuery<T> cq = cb.createQuery(entityClass); //cq is null!!!!
        Root<T> rootEntry = cq.from(entityClass); //cq is null!!!!
        CriteriaQuery<T> all = cq.select(rootEntry);
        TypedQuery<T> allQuery = em.createQuery(all);
        return allQuery.getResultList();
    }
    ...

so i think i'm wrong passing "User.class"... i've to mock this too??? how?

Answer 1

As I can see, you're not mocking it correct.

when(mockedCB.createQuery()).thenReturn(mockedCQ);

So, when mockedCB.createQuery() is called, then mockedCQ will be returned. But then, in your code you have cb.createQuery(entityClass); which is not the same method. So try to change it to

when(mockedCB.createQuery(any())).thenReturn(mockedCQ);