@Test
  public void testHistoryOfEdId1() {
    BiRefIngEntity ing1 = getEntityManager().find(BiRefIngEntity.class, ing1_id);

    BiRefEdEntity rev1 = getAuditReader().find(BiRefEdEntity.class, ed1_id, 1);
    BiRefEdEntity rev2 = getAuditReader().find(BiRefEdEntity.class, ed1_id, 2);

    assert rev1.getReferencing().equals(ing1);
    assert rev2.getReferencing() == null;
  }