public class JPAUnitTestCase {

	private EntityManagerFactory entityManagerFactory;

	@Before
	public void init() {
		entityManagerFactory = Persistence.createEntityManagerFactory( "templatePU" );
	}

	@After
	public void destroy() {
		entityManagerFactory.close();
	}

	@Test(expected = LazyInitializationException.class)
	public void hhh123Test() {
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		entityManager.getTransaction().begin();

		User user = new User();
		entityManager.persist( user );

		Detail detail = new Detail();
		detail.setUser( user );
		entityManager.persist( detail );

		entityManager.getTransaction().commit();
		entityManager.close();

		entityManager = entityManagerFactory.createEntityManager();
		entityManager.getTransaction().begin();

		user = entityManager.find( User.class, user.getId() );

		entityManager.getTransaction().commit();
		entityManager.close();

		Assert.assertNull( user.getDetail() );
	}
}

@Entity
public class User {

	@Id
	@GeneratedValue
	private Long id;

	@OneToOne(mappedBy = "user", fetch = FetchType.LAZY)
	private Detail detail;

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public Detail getDetail() {
		return detail;
	}

	public void setDetail(Detail detail) {
		this.detail = detail;
	}
}

@Entity
public class Detail {

	@Id
	@GeneratedValue
	private Long id;

	@OneToOne(fetch = FetchType.LAZY)
	private User user;

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public User getUser() {
		return user;
	}

	public void setUser(User user) {
		this.user = user;
	}
}