Convert 'Testable' interface into an optional filter.

go/src/infra/gae/libs/gae/brokenfeatures.go

Index: go/src/infra/gae/libs/gae/brokenfeatures.go
diff --git a/go/src/infra/gae/libs/gae/brokenfeatures.go b/go/src/infra/gae/libs/gae/brokenfeatures.go
deleted file mode 100644
index 65bf231c38bfa3af21f523812b2784d1cc561b0a..0000000000000000000000000000000000000000
--- a/go/src/infra/gae/libs/gae/brokenfeatures.go
+++ /dev/null
@@ -1,161 +0,0 @@
-// 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 gae
-
-import (
-	"errors"
-	"fmt"
-	"runtime"
-	"strings"
-	"sync"
-	"unicode"
-	"unicode/utf8"
-)
-
-// FeatureBreaker allows a fake implementation to set and unset broken features.
-// A feature is the Name of some method on the fake. So if you had:
-//   var fake interface{ FeatureBreaker, MCSingleReadWriter } = ...
-//
-// you could do:
-//   fake.BreakFeatures(memcache.ErrServerError, "Add", "Set")
-//
-// and then
-//   fake.Add(...) and fake.Set(...)
-//
-// would return the error.
-//
-// You may also pass nil as the error for BreakFeatures, and the fake will
-// provide some suitable (but generic) error for those features (like a
-// BAD_REQUEST or something like that).
-type FeatureBreaker interface {
-	BreakFeatures(err error, feature ...string)
-	UnbreakFeatures(feature ...string)
-}
-
-// ErrBrokenFeaturesBroken is returned from RunIfNotBroken when BrokenFeatures
-// itself isn't working correctly.
-var ErrBrokenFeaturesBroken = errors.New("brokenFeatures: Unable to retrieve caller information")
-
-// BrokenFeatures implements the FeatureBreaker interface, and is suitable for
-// embedding within a fake service.
-type BrokenFeatures struct {
-	lock sync.Mutex
-
-	broken map[string]error
-
-	// DefaultError is the default error to return when you call
-	// BreakFeatures(nil, ...). If this is unset and the user calls BreakFeatures
-	// with nil, BrokenFeatures will return a generic error.
-	DefaultError error
-}
-
-// BreakFeatures allows you to specify an MCSingleReadWriter function name
-// to cause it to return memcache.ErrServerError. e.g.
-//
-//   m.SetBrokenFeatures("Add")
-//
-// would return memcache.ErrServerError. You can reverse this by calling
-// UnbreakFeatures("Add").
-func (b *BrokenFeatures) BreakFeatures(err error, feature ...string) {
-	b.lock.Lock()
-	defer b.lock.Unlock()
-	if b.broken == nil {
-		b.broken = map[string]error{}
-	}
-
-	for _, f := range feature {
-		b.broken[f] = err
-	}
-}
-
-// UnbreakFeatures is the inverse of BreakFeatures, and will return the named
-// features back to their original functionality.
-func (b *BrokenFeatures) UnbreakFeatures(feature ...string) {
-	b.lock.Lock()
-	defer b.lock.Unlock()
-
-	for _, f := range feature {
-		delete(b.broken, f)
-	}
-}
-
-// RunIfNotBroken is to be called internally by the fake service on every
-// publically-facing method. If it returns an error, the fake should return the
-// error.
-//
-// Example:
-//   type MyService struct { BrokenFeatures }
-//   func (ms *MyService) Thingy() error {
-//     if err := ms.RunIfNotBroken(); err != nil {
-//       return err
-//     }
-//		 ...
-//   }
-//
-//  You can now do ms.SetBrokenFeatures("Thingy"), and Thingy will return an
-//  error.
-//
-//  Note that RunIfNotBroken will keep walking the stack until it finds the
-//  first publically-exported method, which will allow you to put the
-//  RunIfNotBroken call in an internal helper method of your service
-//  implementation.
-//
-//  Additionaly, RunIfNotBroken allows a very primitive form of overriding; it
-//  walks the stack until it finds the first method which is not called
-//  "RunIfNotBroken".  This allows the embedding struct to call into
-//  BrokenFeatures.RunIfNotBroken from another RunIfNotBroken function, and
-//  still have it behave correctly.
-func (b *BrokenFeatures) RunIfNotBroken(f func() error) error {
-	if b.noBrokenFeatures() {
-		return f()
-	}
-
-	var name string
-	for off := 1; ; off++ { // offset of 1 skips ourselves by default
-		// TODO(riannucci): Profile this to see if it's having an adverse
-		// performance impact on tests.
-		fn, _, _, ok := runtime.Caller(off)
-		if !ok {
-			return ErrBrokenFeaturesBroken
-		}
-		toks := strings.Split(runtime.FuncForPC(fn).Name(), ".")
-		name = toks[len(toks)-1]
-		firstRune, _ := utf8.DecodeRuneInString(name)
-		if !unicode.IsUpper(firstRune) {
-			// unexported method, keep walking till we find the first exported
-			// method. Do !IsUpper, since exported is defined by IsUpper and not
-			// !IsLower, and afaik, in unicode-land they're not direct opposites.
-			continue
-		}
-		if name == "RunIfNotBroken" {
-			// Allow users to override RunIfNotBroken, keep walking until we see
-			// a function which is named differently than RunIfNotBroken.
-			continue
-		}
-		break
-	}
-
-	b.lock.Lock()
-	err, ok := b.broken[name]
-	defer b.lock.Unlock()
-
-	if ok {
-		if err != nil {
-			return err
-		}
-		if b.DefaultError != nil {
-			return b.DefaultError
-		}
-		return fmt.Errorf("feature %q is broken", name)
-	}
-
-	return f()
-}
-
-func (b *BrokenFeatures) noBrokenFeatures() bool {
-	b.lock.Lock()
-	defer b.lock.Unlock()
-	return len(b.broken) == 0
-}