Add Info Testable interface, implement for memory.

impl/memory/context.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 (
         "errors"
         "sync"
 
@@ skipping 104 matching lines @@
 // Using this more than once per context.Context will cause a panic.
 func UseWithAppID(c context.Context, aid string) context.Context {
         if c.Value(memContextKey) != nil {
                 panic(errors.New("memory.Use: called twice on the same Context"))
         }
         c = memlogger.Use(c)
 
         memctx := newMemContext(aid)
         c = context.WithValue(c, memContextKey, memctx)
         c = context.WithValue(c, memContextNoTxnKey, memctx)
-        c = context.WithValue(c, giContextKey, &globalInfoData{appid: aid})
-        return useMod(useMail(useUser(useTQ(useRDS(useMC(useGI(c, aid)))))))
+        c = useGID(c, func(mod *globalInfoData) {
+                mod.appid = aid
+        })
+        return useMod(useMail(useUser(useTQ(useRDS(useMC(useGI(c)))))))
 }
 
 func cur(c context.Context) (p *memContext) {
         p, _ = c.Value(memContextKey).(*memContext)
         return
 }
 
 func curNoTxn(c context.Context) (p *memContext) {
         p, _ = c.Value(memContextNoTxnKey).(*memContext)
         return
@@ skipping 58 matching lines @@
         if o != nil && o.Attempts != 0 {
                 attempts = o.Attempts
         }
         for attempt := 0; attempt < attempts; attempt++ {
                 if err := loopBody(attempt >= d.data.txnFakeRetry); err != ds.ErrConcurrentTransaction {
                         return err
                 }
         }
         return ds.ErrConcurrentTransaction
 }