Run Chrome Endure tests with network simulation via Web Page Replay.

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

+/* Copyright (c) 2012 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.
+ *
+ * The scripts in this file will be injected to the http responses when
+ * simulating network via Web Page Replay for Chrome Endure tests.
+ *
+ * If you need to modify this scripts, make sure that you use the same version
+ * of this scripts in both record and replay mode.
+ *
+ * TODO(fdeng):
+ * This file is adapted from deterministic.js in Web Page Replay project.
+ * http://code.google.com/p/web-page-replay/source/browse/trunk/deterministic.js
+ * The value of time_seed is modified to a date far in the future.
+ * This is a workaround for Endure tests for Google apps like Gmail.
+ * The side effect of a future date is unknown and needs future investigation.
+ * A better way to go is to revise the time_seed to
+ * current time each time we record and use the revised scripts for replay.
+ * This can be achieved by modifying Web Page Replay to automatically
+ * revise and save scripts in the archive in record mode and read it
+ * from the archive in replay mode.
+ */
+(function () {
+  var orig_date = Date;
+  var random_count = 0;
+  var date_count = 0;
+  var random_seed = 0.462;
+  var time_seed = 3204251968254; // Changed from default value 1204251968254
+  var random_count_threshold = 25;
+  var date_count_threshold = 25;
+  Math.random = function() {
+    random_count++;
+    if (random_count > random_count_threshold) {
+     random_seed += 0.1;
+     random_count = 1;
+    }
+    return (random_seed % 1);
+  };
+  Date = function() {
+    if (this instanceof Date) {
+      date_count++;
+      if (date_count > date_count_threshold) {
+        time_seed += 50;
+        date_count = 1;
+      }
+      switch (arguments.length) {
+      case 0: return new orig_date(time_seed);
+      case 1: return new orig_date(arguments[0]);
+      default: return new orig_date(arguments[0], arguments[1],
+         arguments.length >= 3 ? arguments[2] : 1,
+         arguments.length >= 4 ? arguments[3] : 0,
+         arguments.length >= 5 ? arguments[4] : 0,
+         arguments.length >= 6 ? arguments[5] : 0,
+         arguments.length >= 7 ? arguments[6] : 0);
+      }
+    }
+    return new Date().toString();
+  };
+  Date.__proto__ = orig_date;
+  Date.prototype.constructor = Date;
+  orig_date.now = function() {
+    return new Date().getTime();
+  };
+})();