Convert 'Testable' interface into an optional filter.

go/src/infra/gae/libs/meta/eg_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 meta
 
 import (
+        "errors"
         "testing"
 
         "golang.org/x/net/context"
 
         "infra/gae/libs/gae"
+        "infra/gae/libs/gae/filters/featureBreaker"
         "infra/gae/libs/gae/memory"
 
         . "github.com/smartystreets/goconvey/convey"
 )
 
 func TestGetEntityGroupVersion(t *testing.T) {
         t.Parallel()
 
         Convey("GetEntityGroupVersion", t, func() {
                 c := memory.Use(context.Background())
+                c, fb := featureBreaker.FilterRDS(c, errors.New("INTERNAL_ERROR"))
                 rds := gae.GetRDS(c)
 
                 aKey, err := rds.Put(rds.NewKey("A", "", 0, nil), gae.DSPropertyMap{
                         "Val": {gae.MkDSProperty(10)},
                 })
                 So(err, ShouldBeNil)
 
                 v, err := GetEntityGroupVersion(c, aKey)
                 So(err, ShouldBeNil)
                 So(v, ShouldEqual, 1)
 
                 So(rds.Delete(aKey), ShouldBeNil)
 
                 v, err = GetEntityGroupVersion(c, rds.NewKey("madeUp", "thing", 0, aKey))
                 So(err, ShouldBeNil)
                 So(v, ShouldEqual, 2)
 
                 v, err = GetEntityGroupVersion(c, rds.NewKey("madeUp", "thing", 0, nil))
                 So(err, ShouldBeNil)
                 So(v, ShouldEqual, 0)
 
-                tDs := rds.(gae.Testable)
-                tDs.BreakFeatures(nil, "Get")
+                fb.BreakFeatures(nil, "Get")
 
                 v, err = GetEntityGroupVersion(c, aKey)
                 So(err.Error(), ShouldContainSubstring, "INTERNAL_ERROR")
         })
 }