third_party/WebKit/LayoutTests/imported/web-platform-tests/hr-time/monotonic-clock.html

   1 <!DOCTYPE html>
   2 <html>
   3 <head>
   4 <meta charset="utf-8" />
   5 <title>window.performance.now() chronology</title>
   6 <link rel="author" title="W3C" href="http://www.w3.org/" />
   7 <link rel="help" href="http://www.w3.org/TR/hr-time/#sec-monotonic-clock"/>
   8 <script src="../../../resources/testharness.js"></script>
   9 <script src="../../../resources/testharnessreport.js"></script>
  10 <link rel="stylesheet" href="../../../resources/testharness.css" />
  11 <script>
  12 test(function() {
  13   assert_true(window.performance.now() > 0, "window.performance.now() returns positive numbers");
  14 }, "window.performance.now() returns a positive number", {assert: "The time values returned when calling the now method MUST be monotonically increasing and not subject to system clock adjustments or system clock skew."});
  15
  16 test(function() {
  17     var now1 = window.performance.now();
  18     var now2 = window.performance.now();
  19     assert_true((now2-now1) >= 0, "window.performance.now() difference is not negative");
  20   },
  21   "window.performance.now() difference is not negative",
  22   {
  23     assert: "The difference between any two chronologically recorded time values returned from the now method MUST never be negative."
  24   }
  25 );
  26
  27 </script>
  28 </head>
  29 <body>
  30 <h1>Description</h1>
  31 <p>This test validates that window.performance.now() follows the monotonic clock requirements.</p>
  32
  33 <div id="log"></div>
  34
  35 </body>
  36 </html>