Some tests didn't recognize that when an object hasn't been modified

in a version, we fall back to non-version data.

Undo wasn't tested properly. The tests didn't get the undo ids
from the transaction log.

src/ZODB/tests/TransactionalUndoVersionStorage.py

@@ -13,8 +13,10 @@ class TransactionalUndoVersionStorage:
         revid_a = self._dostore(oid, data=91)
         revid_b = self._dostore(oid, revid=revid_a, data=92, version=version)
         revid_c = self._dostore(oid, revid=revid_b, data=93, version=version)
+        info=self._storage.undoInfo()
+        tid=info[0]['id']
         self._storage.tpc_begin(self._transaction)
-        oids = self._storage.transactionalUndo(revid_c, self._transaction)
+        oids = self._storage.transactionalUndo(tid, self._transaction)
         self._storage.tpc_vote(self._transaction)
         self._storage.tpc_finish(self._transaction)
         assert len(oids) == 1
@@ -32,14 +34,20 @@ class TransactionalUndoVersionStorage:
         self._storage.tpc_finish(self._transaction)
         assert len(oids) == 1
         assert oids[0] == oid
-        self.assertRaises(POSException.VersionError,
-                          self._storage.load,
-                          oid, version)
+
+        #JF# No, because we fall back to non-version data.
+        #JF# self.assertRaises(POSException.VersionError,
+        #JF#                   self._storage.load,
+        #JF#                   oid, version)
+        data, revid = self._storage.load(oid, version)
+        assert pickle.loads(data) == 92
         data, revid = self._storage.load(oid, '')
         assert pickle.loads(data) == 92
         # ...and undo the commit
+        info=self._storage.undoInfo()
+        tid=info[0]['id']
         self._storage.tpc_begin(self._transaction)
-        oids = self._storage.transactionalUndo(revid, self._transaction)
+        oids = self._storage.transactionalUndo(tid, self._transaction)
         self._storage.tpc_vote(self._transaction)
         self._storage.tpc_finish(self._transaction)
         assert len(oids) == 1
@@ -57,14 +65,19 @@ class TransactionalUndoVersionStorage:
         assert oids[0] == oid
         # The object should not exist in the version now, but it should exist
         # in the non-version
-        self.assertRaises(POSException.VersionError,
-                          self._storage.load,
-                          oid, version)
+        #JF# No, because we fall back
+        #JF# self.assertRaises(POSException.VersionError,
+        #JF#                   self._storage.load,
+        #JF#                   oid, version)
+        data, revid = self._storage.load(oid, version)
+        assert pickle.loads(data) == 91
         data, revid = self._storage.load(oid, '')
         assert pickle.loads(data) == 91
         # Now undo the abort
+        info=self._storage.undoInfo()
+        tid=info[0]['id']
         self._storage.tpc_begin(self._transaction)
-        oids = self._storage.transactionalUndo(revid, self._transaction)
+        oids = self._storage.transactionalUndo(tid, self._transaction)
         self._storage.tpc_vote(self._transaction)
         self._storage.tpc_finish(self._transaction)
         assert len(oids) == 1