try {
UnenhancedType un = newInstance(sub);
em = emf.createEntityManager();
em.getTransaction().begin();
em.persist(un);
un.setStringField("bar");
assertEquals("bar", un.getStringField());
assertPersistenceContext(em, un, true, true, sub);
em.flush();
assertPersistenceContext(em, un, true, true, sub);