order by created, not id (bug 641582)

apps/amo/tasks.py

@@ -50,7 +50,7 @@ def dedupe_approvals(items, **kw):
     for addon in Addon.objects.filter(pk__in=items):
         last = {}
         for activity in (ActivityLog.objects.for_addons(addon)
-                                    .order_by('-id')
+                                    .order_by('-created')
                                     .filter(action__in=LOG_STATUSES)):
             arguments = json.loads(activity._arguments)
             current = {
@@ -71,4 +71,5 @@ def dedupe_approvals(items, **kw):
                 log.info('Deleting duplicate activity log %s '
                          'from addon %s' % (activity.pk, addon.pk))
                 activity.delete()
-            last = current.copy()
+            else:
+                last = current.copy()

apps/amo/tests/test_cron.py

@@ -117,3 +117,14 @@ class TestDedupeApprovals(test_utils.TestCase):
         amo.log(amo.LOG.APPROVE_VERSION, self.addon, self.version)
         dedupe_approvals([self.addon.pk])
         eq_(ActivityLog.objects.for_addons(self.addon).count(), 2)
+
+    def test_dedupe_not_id(self):
+        date_one = datetime.today()
+        date_two = datetime.today() - timedelta(days=1)
+        for x in range(0, 4):
+            log = amo.log(amo.LOG.APPROVE_VERSION, self.addon, self.version)
+            log.update(created=date_one)
+            log = amo.log(amo.LOG.REJECT_VERSION, self.addon, self.version)
+            log.update(created=date_two)
+        dedupe_approvals([self.addon.pk])
+        eq_(ActivityLog.objects.for_addons(self.addon).count(), 2)