Add Info Testable interface, implement for memory.

impl/memory/info.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 (
         "fmt"
         "regexp"
 
         "github.com/luci/gae/impl/dummy"
         "github.com/luci/gae/service/info"
         "golang.org/x/net/context"
 )
 
 type giContextKeyType int
 
 var giContextKey giContextKeyType
 
 // validNamespace matches valid namespace names.
 var validNamespace = regexp.MustCompile(`^[0-9A-Za-z._-]{0,100}$`)
 
+var defaultGlobalInfoData = globalInfoData{
+        // versionID returns X.Y where Y is autogenerated by appengine, and X is
+        // whatever's in app.yaml.
+        versionID: "testVersionID.1",
+        requestID: "test-request-id",
+}
+
+type globalInfoData struct {
+        appid     string
+        namespace string
+        versionID string
+        requestID string
+}
+
 func curGID(c context.Context) *globalInfoData {
-        return c.Value(giContextKey).(*globalInfoData)
+        if gid, ok := c.Value(giContextKey).(*globalInfoData); ok {
+                return gid
+        }
+        return &defaultGlobalInfoData
+}
+
+func useGID(c context.Context, f func(mod *globalInfoData)) context.Context {
+        cur := curGID(c)
+        if cur == nil {
+                cur = &defaultGlobalInfoData
+        }
+
+        clone := *cur
+        f(&clone)
+        return context.WithValue(c, giContextKey, &clone)
 }
 
 // useGI adds a gae.GlobalInfo context, accessible
 // by gae.GetGI(c)
-func useGI(c context.Context, appID string) context.Context {
+func useGI(c context.Context) context.Context {
         return info.SetFactory(c, func(ic context.Context) info.Interface {
                 return &giImpl{dummy.Info(), curGID(ic), ic}
         })
 }
 
-type globalInfoData struct {
-        appid     string
-        namespace string
-}
-
 type giImpl struct {
         info.Interface
         *globalInfoData
         c context.Context
 }
 
 var _ = info.Interface((*giImpl)(nil))
 
 func (gi *giImpl) GetNamespace() string {
         return gi.namespace
 }
 
 func (gi *giImpl) Namespace(ns string) (ret context.Context, err error) {
         if !validNamespace.MatchString(ns) {
                 return nil, fmt.Errorf("appengine: namespace %q does not match /%s/", ns, validNamespace)
         }
-        return context.WithValue(gi.c, giContextKey, &globalInfoData{gi.appid, ns}), nil
+
+        return useGID(gi.c, func(mod *globalInfoData) {
+                mod.namespace = ns
+        }), nil
 }
 
 func (gi *giImpl) MustNamespace(ns string) context.Context {
         ret, err := gi.Namespace(ns)
         if err != nil {
                 panic(err)
         }
         return ret
 }
 
 func (gi *giImpl) AppID() string {
         return gi.appid
 }
 
 func (gi *giImpl) FullyQualifiedAppID() string {
         return gi.appid
 }
 
 func (gi *giImpl) IsDevAppServer() bool {
         return true
 }
 
 func (gi *giImpl) VersionID() string {
-        // VersionID returns X.Y where Y is autogenerated by appengine, and X is
-        // whatever's in app.yaml.
-        return "testVersionID.1"
+        return curGID(gi.c).versionID
 }
+
+func (gi *giImpl) RequestID() string {
+        return curGID(gi.c).requestID
+}
+
+func (gi *giImpl) Testable() info.Testable {
+        return gi
+}
+
+func (gi *giImpl) SetVersionID(v string) context.Context {
+        return useGID(gi.c, func(mod *globalInfoData) {
+                mod.versionID = v
+        })
+}
+
+func (gi *giImpl) SetRequestID(v string) context.Context {
+        return useGID(gi.c, func(mod *globalInfoData) {
+                mod.requestID = v
+        })
+}