Make obtaining the Testable interface actually part of the interface.

filter/count/tq.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 count
 
 import (
         "golang.org/x/net/context"
 
         tq "github.com/luci/gae/service/taskqueue"
@@ skipping 24 matching lines @@
 }
 
 func (t *tqCounter) Purge(queueName string) error {
         return t.c.Purge.up(t.tq.Purge(queueName))
 }
 
 func (t *tqCounter) Stats(queueNames []string, cb tq.RawStatsCB) error {
         return t.c.Stats.up(t.tq.Stats(queueNames, cb))
 }
 
+func (t *tqCounter) Testable() tq.Testable {
+        return t.tq.Testable()
+}
+
 // FilterTQ installs a counter TaskQueue filter in the context.
 func FilterTQ(c context.Context) (context.Context, *TQCounter) {
         state := &TQCounter{}
         return tq.AddRawFilters(c, func(ic context.Context, tq tq.RawInterface) tq.RawInterface {
                 return &tqCounter{state, tq}
         }), state
 }