Fix backreferences to the same table

test/test_db.py

@@ -68,9 +68,13 @@ def test_subgroups(db):
     snw = db.save(examples.Group(name="Strange New Worlds", members=[pike]))
 
     starfleet = db.save(examples.Group(name="Starfleet", groups=[tos, snw]))
+    tos = db.table("Group").get(doc_id=tos.doc_id)
+    snw = db.table("Group").get(doc_id=snw.doc_id)
     assert tos in starfleet.groups
     assert snw in starfleet.groups
 
+    assert tos.parent.uid == starfleet.uid
+
     unique_users = set([user for group in starfleet.groups for user in group.members])
 
     kirk = db.table("User").get(doc_id=kirk.doc_id)