Handle multiple modifications to distribution metrics correctly.

appengine_module/gae_ts_mon/test/memcache_metric_store_test.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import operator
 import random
 import unittest
 
 import gae_ts_mon
 import mock
 
 from google.appengine.ext import testbed
 from google.appengine.api.memcache import memcache_service_pb
 
 from infra_libs.ts_mon import memcache_metric_store
@@ skipping 142 matching lines @@
     with self.assertRaises(errors.MonitoringDecreasingValueError):
       self.store.modify_multi([
           metric_store.Modification(
               self.gauge_metric.name, (), 'set', (41, True))])
 
   def test_modify_multi_incr(self):
     self.gauge_metric.set(42)
 
     self.store.modify_multi([
         metric_store.Modification(
-            self.gauge_metric.name, (), 'incr', (4, operator.add))])
+            self.gauge_metric.name, (), 'incr', (4, None))])
 
     self.assertEqual(46, self.gauge_metric.get())
 
   def test_modify_multi_incr_negative(self):
     with self.assertRaises(errors.MonitoringDecreasingValueError):
       self.store.modify_multi([
           metric_store.Modification(
-              self.gauge_metric.name, (), 'incr', (-1, operator.add))])
+              self.gauge_metric.name, (), 'incr', (-1, None))])
 
   def test_modify_multi_bad_type(self):
     with self.assertRaises(errors.UnknownModificationTypeError):
       self.store.modify_multi([
           metric_store.Modification(
-              self.gauge_metric.name, (), 'bad', (-1, operator.add))])
+              self.gauge_metric.name, (), 'bad', (-1, None))])
 
   def test_modify_multi_with_fields(self):
     self.store.modify_multi([
         metric_store.Modification(
             self.gauge_metric.name, (('f', 1),), 'set', (41, False)),
         metric_store.Modification(
             self.gauge_metric.name, (('f', 2),), 'set', (42, False))])
 
     self.assertEqual(41, self.gauge_metric.get({'f': 1}))
     self.assertEqual(42, self.gauge_metric.get({'f': 2}))