Spring Boot + JPA + Lazy bi-directional collection testing

Question

I'm new to JPA and Spring Data and I've faced problem with testing my application. I have two entities in my Spring boot application:

@Getter
@Setter
@Entity
public class User extends SomeBasicEntity {

    @NotNull
    @Column(unique = true)
    private String login;

    @NotNull
    private String password;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "user", cascade = CascadeType.ALL)
    @JsonManagedReference
    private List<Role> roles;

}

@Getter
@Setter
@Entity
@Table(name = "ROLE")
public class Role extends SomeBasicEntity {

    @NotNull
    private String name;

    @ManyToOne
    @NotNull
    @JsonBackReference
    private User user;


}

I have implemented dedicated JPA repositories for them (as JpaRepository). I have also implemented transactional facade for the management:

@Service
@Transactional
public class Facade {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private RoleRepository roleRepository;

    public User addNewUser(User user) {
        return userRepository.save(user);
    }

    public Role addNewRole(Role role, User user) {
        role.setUser(user);
        return roleRepository.save(role);
    }

    public User findUserByLogin(String login) {
        User user = userRepository.findByLogin(login);
        if (user != null) {
            return user;
        } else {
            throw new FacadeRuntimeException("User " + login + " does not exists");
        }
    }
}

Finally, I've created RestController for using the facade (I've hardcoded login name value just for test purposes):

@RestController
@RequestMapping(value = "/users")
public class UserController {

    @Autowired
    private Facade facade;

    @RequestMapping(value = "/login", method = RequestMethod.GET)
    public User getUserByLogin() {
        User user = facade.findUserByLogin("jahu");
        return user;
    }
}

And now when I run the application, use facade methods to create user and role (code is irrelevant so I dont paste it here) and check REST response on localhost/users/login there is properly serialized User object WITH list of roles (with single role I've created actually).

Question 1: Why roles are present in Json object whereas I didn't explictly call getRoles on the user object? With lazy fetch type I believe collection should be retrived only when getter is called (maybe JSON serializer is calling the method?)

Nevertheless, I have second problem as I want to test my facade with jUnit (on h2 db), however in test method the roles on User object are always null (even if I explicltly call getter):

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = FacadeApplication.class)
@Transactional
public class FacadeTest {

    private static final String USER_LOGIN = "jahu";
    private static final String ROLE_NAME = "role name";

    @Autowired
    Facade sut;

    @Before
    public void setUp() throws Exception {
        User user = new User();
        user.setLogin(USER_LOGIN);
        user.setPassword("jahu");

        user = sut.addNewUser(user);

        Role role = new Role();
        role.setName(ROLE_NAME);
        sut.addNewRole(role, user);
    }

    @Test
    public void shouldFindUserRoles() {
        User user = sut.findUserByLogin(USER_LOGIN);

        assertThat(user).isNotNull();
        assertThat(user.getLogin()).isEqualTo(USER_LOGIN);
        List<Role> roles = user.getRoles(); // HERE I call the getter
        assertThat(roles).isNotNull().isNotEmpty();
    }

}

Question 2: Why can I not access roles in test context even though I am using the same method as in RestController (where roles are always obtained)? Without it I am not able to fully test my app and it concerns me very much.

Note: entity names are just for description of the problem, so please don't suggest that I should remodel my entities in order to assign Role to User.