Can't mock EntityManager jMockit

Question

I am having some trouble trying to mock out an EntityManager in tests using jMockit.

I have this base class:

public abstract class BaseEntityManager {

    @PersistenceContext private EntityManager entityManager;

    protected EntityManager getEntityManager(){
         return entityManager;
    }
}

And a class that extends it:

@Stateless
public class PlayerManager extends BaseEntityManager{

    public Collection<PlayerDTO> getPlayersByDraftClass(int draftClass){
        EntityManager em = getEntityManager();
        Query query = em.createNamedQuery("Player.findByDraftClass", Player.class);
        query.setParameter("draftClass", draftClass);
        List<Player> players =  query.getResultList();
        return convertPlayersToPlayerDTOs(players);
    }
    ...some other methods
}

In my test I have :

public class PlayerManagerTest {

    @Injectable EntityManager em;
    @Tested PlayerManager pm;

    @Test
    public void testGetPlayersByDraftClass_PlayersReturned() throws FYPException{

        final List<Player> players = new ArrayList();
        players.add(createBasicPlayer(PLAYER_1_ID, PLAYER_1_NAME, PLAYER_1_POSITION));
        players.add(createBasicPlayer(PLAYER_2_ID, PLAYER_2_NAME, PLAYER_2_POSITION));

        new NonStrictExpectations(){
            @Mocked TypedQuery playerQuery;
            {   
                em.createNamedQuery(anyString, Player.class);
                result = playerQuery;

                playerQuery.getResultList();
                result = players;
            }
        };

        final ArrayList<PlayerDTO> result = (ArrayList<PlayerDTO>)pm.getPlayersByDraftClass(TEST_YEAR);

        new Verifications(){{
            assertNotNull("The list of players should not be null", result);
            assertFalse("The list should not be empty", result.isEmpty());
            assertEquals("The number of dtos returned should match the query result", players.size(), result.size());
            assertDTOsMatchEntities(players, result);
        }};

    }
    ...some other tests and helper methods
}

I am getting a null pointer exception on the line playerQuery.getResultList(), so I assume playerQuery is never being initialised as it is not registering em.createNamedQuery(anyString, Player.class) as ever being called.

I have even tried moving the EntityManager into the PlayerManager class and therefore removing the need to call getEntityManager(), but it still throws the same null pointer.

Answer 1

Move the @Mocked TypedQuery playerQuery local field to the test method, as a mock parameter.