fp.clearFetchGroups().removeFetchGroup(FetchGroup.NAME_DEFAULT);
fp.clearFields();
fp.addField(FetchA.class, "b");
fp.addField(FetchBase.class, "text");
FetchA a = (FetchA) em.createQuery(JPQL).getSingleResult();
em.close();
FetchB b = a.getB();
assertNotNull(b);
assertEquals("a1", a.getText());
assertEquals("b1", b.getText());
}