Mockito在createCriteria中測試DAO獲取NullPointerException

Question

我正在嘗試爲dao圖層寫入測試。我從休眠的工作，當我試圖測試我的方法getAll我得到異常NullPointerException從createCriteria行，我不知道如何解決問題。

這是我的例外：

java.lang.NullPointerException 
    at dao.UserDaoTest.testFindAll(UserDaoTest.java:69) 

這是我的測試類：

@Mock 
private SessionFactory sessionFactory; 
@Mock 
private Session session; 
@Mock 
private Transaction transaction; 
@InjectMocks 
private UserDaoImpl userDao; 

private User user; 

@Before 
public void setUpUser(){ 
    user = new User(); 
    user.setName("is name"); 
    when(sessionFactory.openSession()).thenReturn(session); 
    when(session.beginTransaction()).thenReturn(transaction); 
} 
@Test 
public void testFindAll(){ 
    List<User> userList = new ArrayList<>(); 
    userList.add(user); 
    when(session.createCriteria(User.class).list()).thenReturn(userList); //NullPointerException 
    List<User> userList1 = userDao.findAll(); 
    assertThat(userList1, is(userList)); 
} 

這是DAO類：

private Session session; 
private Transaction transaction; 
public List<User> findAll() { 
    List<User> userList = null; 
    session = sessionFactory.openSession(); 
    transaction = null; 
    try{ 
     transaction = session.beginTransaction(); 
     userList = session.createCriteria(User.class).list(); 
     transaction.commit(); 
    }catch (HibernateException e) { 
     if (transaction!=null) { 
      transaction.rollback(); 
     } 
     e.printStackTrace(); 
    }finally { 
     session.close(); 
    } 
    return userList; 
} 

Answer 1

嘗試在testFindAll是這樣的（）

Criteria aCriteria = Mockito.mock(Criteria.class); 
when(session.createCriteria(User.class)).thenReturn(aCriteria); 
when(aCriteria.list()).thenReturn(userList);