private EntityManager em;
@Test
public void userDao_should_create_user_so_it_could_be_retrieved_from_userDao_by_username() {
// given
User created = new User("username1");
// when
userDao.createUser(created);
User retrieved = userDao.getForUsername("username1");
// then
assertTrue(em.contains(created));
assertTrue(em.contains(retrieved));
Assert.assertEquals(created, retrieved);