如何模拟和单元测试javax.persistence.EntityManager和javax.persistence.Query？获取NullPointerException

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {PersistenceConfig.class})
public class MyRepositoryTest {

    @PersistenceContext
    private EntityManager entityManager;

    @Test
    public void testFindAll() {
        Query query = entityManager.createQuery("SELECT e FROM Entity e");
        List<Entity> results = query.getResultList();
        // 断言和测试逻辑
    }
}

@RunWith(MockitoJUnitRunner.class)
public class MyRepositoryTest {

    @Mock
    private EntityManager entityManager;

    @Mock
    private Query query;

    @InjectMocks
    private MyRepository repository;

    @Before
    public void setUp() {
        when(entityManager.createQuery(anyString())).thenReturn(query);
        when(query.getResultList()).thenReturn(Collections.singletonList(new Entity()));
    }

    @Test
    public void testFindAll() {
        List<Entity> results = repository.findAll();
        // 断言和测试逻辑
    }
}