Spring boot test: Test passes, but should not (false positive)

I have Spring Boot project with test that does not fail (but should).

Am I doing something wrong or it is a issue with Spring?

For an small example I have created a small project with 2 entities (User and Category) and one Controller class that has DELETE method (http://ift.tt/1TdtWDc).

Category entity has an id of User entity without cascade option, so it should fail while deleting a User that has category:

@Entity
@Table(name = "user")
public class User {

    @Id
    @GeneratedValue
    private long id;
    private String name;
    ...
}

@Entity
@Table(name = "category")
public class Category {

    @Id
    @GeneratedValue
    private long id;
    private String name;

    @ManyToOne
    @JoinColumn(name = "user_id", nullable = false)
    private User user;
    ...
}

Controller is also is pretty simple:

@RestController
@RequestMapping(value = "/users", produces = "application/json;charset=UTF-8")
public class UserCategory {

    @Autowired
    private UserRepository userRepository;

    @ResponseStatus(HttpStatus.OK)
    @RequestMapping(value = "/{id}", method = DELETE, consumes =   MediaType.ALL_VALUE)
    public void deleteCategory(@PathVariable Long id) {
        User user = userRepository.getOne(id);
        userRepository.delete(user);
    }
}

And finally a test:

@Transactional
@WebAppConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = DemoApplication.class)
public class DemoApplicationTests {

    @Autowired
    protected WebApplicationContext context;

    protected MockMvc mockMvc;

    @Before
    public void setUp() {
        mockMvc = MockMvcBuilders.webAppContextSetup(this.context).build();
    }

    @Test
    public void testName() throws Exception {
        mockMvc.perform(delete("/users/1"))
                .andExpect(status().isOk());

//      EntityManagerFactory entityManagerFactory = context.getBean(EntityManagerFactory.class);
//      SessionFactory sessionFactory = entityManagerFactory.unwrap(SessionFactory.class);
//      sessionFactory.getCurrentSession().flush();
    }
}

Test will fail in case I remove @Transactional annotation from DemoApplicationTests, but in this case changes will be committed to a DB.

Commented 3 lines in the test does not help either.