third_party/WebKit/LayoutTests/fast/dom/timer-throttling-background-page-near-alignment-interval.html

   1 <html>
   2 <head>
   3     <script src="../../resources/js-test.js"></script>
   4     <script>
   5         description('<a href="http://crbug.com/259680">Bug 259680</a>: JavaScript setInterval lagging behind');
   6
   7         var jsTestIsAsync = true;
   8         var intervalDuration = 1000;
   9         var testDuration = 4000;
  10         var expectedNumFires = 4;
  11         var numFires = 0;
  12         var tolerance = 1;
  13
  14         var intervalID;
  15         var startTime;
  16
  17         function timerFired()
  18         {
  19             ++numFires;
  20
  21             var currentTime = new Date().getTime();
  22             if (currentTime >= startTime + testDuration) {
  23                 shouldBeCloseTo("numFires", expectedNumFires, tolerance);
  24
  25                 clearInterval(intervalID);
  26                 finishJSTest();
  27                 return;
  28             }
  29         }
  30
  31         function runTest()
  32         {
  33             if (!window.testRunner) {
  34                 debug('This test requires testRunner');
  35                 return;
  36             }
  37
  38             testRunner.dumpAsText();
  39
  40             testRunner.setPageVisibility("hidden");
  41             startTime = new Date().getTime();
  42             intervalID = window.setInterval(timerFired, intervalDuration);
  43         }
  44     </script>
  45 </head>
  46 <body onload="runTest()">
  47     <p>
  48     This test ensures that intervals on background pages whose duration is close to the timer alignment interval don't miss every other firing.
  49     </p>
  50 </body>
  51 </html>