DemoStorage: fix history()

- It failed with oids that already exist in the base storage.
- MappingStorage returned timestamps in wrong format.

src/ZODB/DemoStorage.py

@@ -113,7 +113,7 @@ class DemoStorage(ConflictResolvingStorage):
     def _copy_methods_from_changes(self, changes):
         for meth in (
             '_lock_acquire', '_lock_release',
-            'getSize', 'history', 'isReadOnly',
+            'getSize', 'isReadOnly',
             'sortKey', 'tpc_transaction', 'tpc_vote',
             ):
             setattr(self, meth, getattr(changes, meth))
@@ -138,6 +138,20 @@ class DemoStorage(ConflictResolvingStorage):
         except ZODB.POSException.POSKeyError:
             return self.base.getTid(oid)
 
+    def history(self, oid, size=1):
+        try:
+            r = self.changes.history(oid, size)
+        except ZODB.POSException.POSKeyError:
+            r = []
+        size -= len(r)
+        if size:
+            try:
+                r += self.base.history(oid, size)
+            except ZODB.POSException.POSKeyError:
+                if not r:
+                    raise
+        return r
+
     def iterator(self, start=None, end=None):
         for t in self.base.iterator(start, end):
             yield t

src/ZODB/MappingStorage.py

@@ -106,7 +106,7 @@ class MappingStorage(object):
         tids.reverse()
         return [
             dict(
-                time = ZODB.TimeStamp.TimeStamp(tid),
+                time = ZODB.TimeStamp.TimeStamp(tid).timeTime(),
                 tid = tid,
                 serial = tid,
                 user_name = self._transactions[tid].user,

src/ZODB/tests/HistoryStorage.py

@@ -17,45 +17,31 @@ Any storage that supports the history() method should be able to pass
 all these tests.
 """
 
+from time import time
 from ZODB.tests.MinPO import MinPO
 
 class HistoryStorage:
     def checkSimpleHistory(self):
-        eq = self.assertEqual
+        self._checkHistory((11, 12, 13))
+
+    def _checkHistory(self, data):
+        start = time()
         # Store a couple of revisions of the object
         oid = self._storage.new_oid()
         self.assertRaises(KeyError,self._storage.history,oid)
-        revid1 = self._dostore(oid, data=MinPO(11))
-        revid2 = self._dostore(oid, revid=revid1, data=MinPO(12))
-        revid3 = self._dostore(oid, revid=revid2, data=MinPO(13))
+        revids = [None]
+        for data in data:
+            revids.append(self._dostore(oid, revids[-1], MinPO(data)))
+        revids.reverse()
+        del revids[-1]
         # Now get various snapshots of the object's history
-        h = self._storage.history(oid, size=1)
-        eq(len(h), 1)
-        d = h[0]
-        eq(d['tid'], revid3)
-        # Try to get 2 historical revisions
-        h = self._storage.history(oid, size=2)
-        eq(len(h), 2)
-        d = h[0]
-        eq(d['tid'], revid3)
-        d = h[1]
-        eq(d['tid'], revid2)
-        # Try to get all 3 historical revisions
-        h = self._storage.history(oid, size=3)
-        eq(len(h), 3)
-        d = h[0]
-        eq(d['tid'], revid3)
-        d = h[1]
-        eq(d['tid'], revid2)
-        d = h[2]
-        eq(d['tid'], revid1)
-        # There should be no more than 3 revisions
-        h = self._storage.history(oid, size=4)
-        eq(len(h), 3)
-        d = h[0]
-        eq(d['tid'], revid3)
-        d = h[1]
-        eq(d['tid'], revid2)
-        d = h[2]
-        eq(d['tid'], revid1)
-
+        for i in range(1, 1 + len(revids)):
+            h = self._storage.history(oid, size=i)
+            self.assertEqual([d['tid'] for d in h], revids[:i])
+        # Check results are sorted by timestamp, in descending order.
+        a = time()
+        for d in h:
+            b = a
+            a = d['time']
+            self.assertLess(a, b)
+        self.assertLess(start, a)

src/ZODB/tests/testDemoStorage.py

@@ -87,6 +87,23 @@ class DemoStorageTests(
         pass # we don't support undo yet
     checkUndoZombie = checkLoadBeforeUndo
 
+    def checkBaseHistory(self):
+        def base_only():
+            yield 11
+            yield 12
+            yield 13
+            self._storage = self._storage.push()
+        self._checkHistory(base_only())
+        self._storage = self._storage.pop()
+        def base_and_changes():
+            yield 11
+            yield 12
+            self._storage = self._storage.push()
+            yield 13
+            yield 14
+        self._checkHistory(base_and_changes())
+        self._storage = self._storage.pop()
+
 
 class DemoStorageHexTests(DemoStorageTests):
 
@@ -149,7 +166,7 @@ def testSomeDelegation():
     ...         six.print_(self.name, 'size')
     ...     def close(self):
     ...         six.print_(self.name, 'closed')
-    ...     sortKey = __len__ = history = getTid = None
+    ...     sortKey = __len__ = getTid = None
     ...     tpc_finish = tpc_vote = tpc_transaction = None
     ...     _lock_acquire = _lock_release = lambda self: None
     ...     getName = lambda self: 'S'