public void testFetchBySuperClassField() {
OpenJPAEntityManager em = emf.createEntityManager();
FetchPlan fp = em.getFetchPlan();
fp.setExtendedPathLookup(true);
fp.clearFetchGroups();
fp.clearFields();
fp.addField(FetchA.class, "b");
fp.addField(FetchBase.class, "text");
FetchA a = (FetchA) em.createQuery(JPQL).getSingleResult();
em.close();