chrome/test/data/chrome_endure/webpagereplay/wpr_deterministic.js

   1 /* Copyright (c) 2012 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  * The scripts in this file will be injected to the http responses when
   6  * simulating network via Web Page Replay for Chrome Endure tests.
   7  *
   8  * If you need to modify this scripts, make sure that you use the same version
   9  * of this scripts in both record and replay mode.
  10  *
  11  * TODO(fdeng):
  12  * This file is adapted from deterministic.js in Web Page Replay project.
  13  * http://code.google.com/p/web-page-replay/source/browse/trunk/deterministic.js
  14  * The value of time_seed is modified to a date far in the future.
  15  * This is a workaround for Endure tests for Google apps like Gmail.
  16  * The side effect of a future date is unknown and needs future investigation.
  17  * A better way to go is to revise the time_seed to
  18  * current time each time we record and use the revised scripts for replay.
  19  * This can be achieved by modifying Web Page Replay to automatically
  20  * revise and save scripts in the archive in record mode and read it
  21  * from the archive in replay mode.
  22  */
  23 (function () {
  24   var orig_date = Date;
  25   var random_count = 0;
  26   var date_count = 0;
  27   var random_seed = 0.462;
  28   var time_seed = 3204251968254; // Changed from default value 1204251968254
  29   var random_count_threshold = 25;
  30   var date_count_threshold = 25;
  31   Math.random = function() {
  32     random_count++;
  33     if (random_count > random_count_threshold) {
  34      random_seed += 0.1;
  35      random_count = 1;
  36     }
  37     return (random_seed % 1);
  38   };
  39   Date = function() {
  40     if (this instanceof Date) {
  41       date_count++;
  42       if (date_count > date_count_threshold) {
  43         time_seed += 50;
  44         date_count = 1;
  45       }
  46       switch (arguments.length) {
  47       case 0: return new orig_date(time_seed);
  48       case 1: return new orig_date(arguments[0]);
  49       default: return new orig_date(arguments[0], arguments[1],
  50          arguments.length >= 3 ? arguments[2] : 1,
  51          arguments.length >= 4 ? arguments[3] : 0,
  52          arguments.length >= 5 ? arguments[4] : 0,
  53          arguments.length >= 6 ? arguments[5] : 0,
  54          arguments.length >= 7 ? arguments[6] : 0);
  55       }
  56     }
  57     return new Date().toString();
  58   };
  59   Date.__proto__ = orig_date;
  60   Date.prototype.constructor = Date;
  61   orig_date.now = function() {
  62     return new Date().getTime();
  63   };
  64 })();