A simple memcache lock for appengine.

go/src/infra/gae/libs/wrapper/memory/memcache_test.go

 // 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.
 
 package memory
 
 import (
         "infra/gae/libs/wrapper"
         "infra/gae/libs/wrapper/unsafe"
         "testing"
@@ skipping 10 matching lines @@
 
         Convey("memcache", t, func() {
                 now := time.Now()
                 timeNow := func(context.Context) time.Time {
                         ret := now
                         now = now.Add(time.Second)
                         return ret
                 }
                 c := Use(wrapper.SetTimeNowFactory(context.Background(), timeNow))
                 mc := wrapper.GetMC(c)
-                mci := mc.(*memcacheImpl)
+                mci := wrapper.GetMC(c).(*memcacheImpl)
+                So(mc, ShouldNotEqual, mci) // two impls with the same memcacheData
 
                 Convey("implements MCSingleReadWriter", func() {
                         Convey("Add", func() {
                                 itm := &memcache.Item{
                                         Key:        "sup",
                                         Value:      []byte("cool"),
                                         Expiration: time.Second,
                                 }
                                 err := mc.Add(itm)
                                 So(err, ShouldBeNil)
@@ skipping 168 matching lines @@
                         testItem := &memcache.Item{
                                 Key:   "sup",
                                 Value: []byte("cool"),
                         }
                         unsafe.MCSetCasID(testItem, 1)
                         So(el, ShouldResemble, testItem)
                 })
 
         })
 }