Info Memory: Implement dummy ServiceAccount()

impl/memory/info_test.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package memory
 
 import (
         "testing"
 
         "github.com/luci/gae/service/info"
         "golang.org/x/net/context"
 
         . "github.com/smartystreets/goconvey/convey"
 )
 
 func TestMustNamespace(t *testing.T) {
         Convey("Testable interface works", t, func() {
                 c := UseWithAppID(context.Background(), "dev~app-id")
 
                 // Default value.
                 So(info.AppID(c), ShouldEqual, "app-id")
                 So(info.FullyQualifiedAppID(c), ShouldEqual, "dev~app-id")
                 So(info.RequestID(c), ShouldEqual, "test-request-id")
+                sa, err := info.ServiceAccount(c)
+                So(err, ShouldBeNil)
+                So(sa, ShouldEqual, "user@example.com")
 
                 // Setting to "override" applies to initial context.
                 c = info.GetTestable(c).SetRequestID("override")
                 So(info.RequestID(c), ShouldEqual, "override")
 
                 // Derive inner context, "override" applies.
                 c = info.MustNamespace(c, "valid_namespace_name")
                 So(info.RequestID(c), ShouldEqual, "override")
         })
 }