MD Settings: FakeSettingsPrivate for tests

chrome/browser/resources/settings/prefs/prefs.js

 /* 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. */
 
 /**
  * @fileoverview
  * 'settings-prefs' exposes a singleton model of Chrome settings and
  * preferences, which listens to changes to Chrome prefs whitelisted in
  * chrome.settingsPrivate. When changing prefs in this element's 'prefs'
  * property via the UI, the singleton model tries to set those preferences in
@@ skipping 249 matching lines @@
         type: Object,
         value: function() { return {}; },
       },
     },
 
     // Listen for the manually fired prefs-changed event.
     listeners: {
       'prefs-changed': 'prefsChanged_',
     },
 
-    settingsApi_: chrome.settingsPrivate,
-
     initialize: function() {
       // Only initialize once (or after resetForTesting() is called).
       if (this.initialized_)
         return;
       this.initialized_ = true;
 
-      // Set window.mockApi to pass a custom settings API, i.e. for tests.
-      // TODO(michaelpg): don't use a global.
-      if (window.mockApi)
-        this.settingsApi_ = window.mockApi;
-
-      this.settingsApi_.onPrefsChanged.addListener(
+      chrome.settingsPrivate.onPrefsChanged.addListener(

[Dan Beam, 2015/11/17 23:01:15]

why are you [able to] undo this?

[michaelpg, 2015/11/17 23:51:51]

I don't like this because:
  * checking for a global sucks
  * grepping chrome.settingsPrivate.foo to check usage becomes ineffective
  * i don't think Closure can type-check the previous version because there's no
"type" for the API (I confirmed it wasn't checking usage of this.settingsApi_,
but IDK if it would be possible to tell Closure that this.settingsApi_ is an
"alias" for chrome.settingsPrivate)

As far as ability, this is done by the fake setting chrome.settingsPrivate to
itself.

           this.onSettingsPrivatePrefsChanged_.bind(this));
-      this.settingsApi_.getAllPrefs(
+      chrome.settingsPrivate.getAllPrefs(
           this.onSettingsPrivatePrefsFetched_.bind(this));
     },
 
     /**
      * Polymer callback for changes to this.prefs.
      * @param {!CustomEvent} e
      * @param {!{path: string}} change
      * @private
      */
     prefsChanged_: function(e, change) {
       if (!CrSettingsPrefs.isInitialized)
         return;
 
       var key = this.getPrefKeyFromPath_(change.path);
       var prefStoreValue = this.lastPrefValues_[key];
 
       var prefObj = /** @type {chrome.settingsPrivate.PrefObject} */(
           this.get(key, this.prefs));
 
       // If settingsPrivate already has this value, do nothing. (Otherwise,
       // a change event from settingsPrivate could make us call
       // settingsPrivate.setPref and potentially trigger an IPC loop.)
       if (deepEqual(prefStoreValue, prefObj.value))
         return;
 
-      this.settingsApi_.setPref(
+      chrome.settingsPrivate.setPref(
           key,
           prefObj.value,
           /* pageId */ '',
           /* callback */ this.setPrefCallback_.bind(this, key));
     },
 
     /**
      * Called when prefs in the underlying Chrome pref store are changed.
      * @param {!Array<!chrome.settingsPrivate.PrefObject>} prefs
      *     The prefs that changed.
@@ skipping 19 matching lines @@
      * @param {string} key The key used in the call to setPref.
      * @param {boolean} success True if setting the pref succeeded.
      * @private
      */
     setPrefCallback_: function(key, success) {
       if (success)
         return;
 
       // Get the current pref value from chrome.settingsPrivate to ensure the
       // UI stays up to date.
-      this.settingsApi_.getPref(key, function(pref) {
+      chrome.settingsPrivate.getPref(key, function(pref) {
         this.updatePrefs_([pref]);
       }.bind(this));
     },
 
     /**
      * Updates the prefs model with the given prefs.
      * @param {!Array<!chrome.settingsPrivate.PrefObject>} newPrefs
      * @private
      */
     updatePrefs_: function(newPrefs) {
@@ skipping 42 matching lines @@
     /**
      * Resets the element so it can be re-initialized with a new prefs state.
      */
     resetForTesting: function() {
       this.prefs = undefined;
       this.lastPrefValues_ = {};
       this.initialized_ = false;
     },
   });
 })();