chrome/browser/resources/chromeos/chromevox/testing/callback_helper.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * Creates wrappers for callbacks and calls testDone() when all callbacks
   7  * have been invoked.
   8  * @param {testing.Test} fixture
   9  */
  10 function CallbackHelper(fixture) {
  11   /** @type {Object} fixture */
  12   this.fixture_ = fixture;
  13   /** @type {number} */
  14   this.pendingCallbacks_ = 0;
  15 }
  16
  17 CallbackHelper.prototype = {
  18   /**
  19    * @param {Function=} opt_callback
  20    * @return {Function}
  21    */
  22   wrap: function(opt_callback) {
  23     var callback = opt_callback || function() {};
  24     var savedArgs = new SaveMockArguments();
  25     var lastCall = null;
  26     var completionAction = callFunctionWithSavedArgs(savedArgs, function() {
  27       if (lastCall) {
  28         throw new Error('Called more than once, first call here: ' + lastCall);
  29       } else {
  30         lastCall = new Error().stack;
  31       }
  32       callback.apply(this.fixture_, arguments);
  33       if (--this.pendingCallbacks_ <= 0)
  34         CallbackHelper.testDone_();
  35     }.bind(this));
  36     // runAllActionsAsync catches exceptions and puts them in the test
  37     // framework's list of errors and fails the test if appropriate.
  38     var runAll = runAllActionsAsync(WhenTestDone.ASSERT, completionAction);
  39     ++this.pendingCallbacks_;
  40     return function() {
  41       savedArgs.arguments = Array.prototype.slice.call(arguments);
  42       runAll.invoke();
  43     }
  44   }
  45 };
  46
  47 /**
  48  * @private
  49  */
  50 CallbackHelper.testDone_ = this.testDone;
  51 // Remove testDone for public use since direclty using it conflicts with
  52 // this callback helper.
  53 delete this.testDone;