dom/performance/tests/test_performance_navigation_timing.html

   1 <!DOCTYPE HTML>
   2 <html>
   3     <!--
   4     https://bugzilla.mozilla.org/show_bug.cgi?id=1462891
   5     -->
   6     <head>
   7         <title>Test for Bug 1462891</title>
   8         <meta http-equiv="content-type" content="text/html; charset=UTF-8">
   9         <script src="/tests/SimpleTest/SimpleTest.js"></script>
  10     </head>
  11     <body>
  12         <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1462891">Mozilla Bug 1462891 - Navigation Timing API</a>
  13         <div id="content">
  14         </div>
  15         <pre id="test">
  16             <script class="testbody" type="text/javascript">
  17              var index = 0;
  18              let isRounded = (x, shouldRound, expectedPrecision) => {
  19                 if (!shouldRound)
  20                    return true;
  21
  22                 let rounded = (Math.floor(x / expectedPrecision) * expectedPrecision);
  23                 // First we do the perfectly normal check that should work just fine
  24                 if (rounded === x || x === 0)
  25                 return true;
  26
  27                 // When we're diving by non-whole numbers, we may not get perfect
  28                 // multiplication/division because of floating points.
  29                 // When dealing with ms since epoch, a double's precision is on the order
  30                 // of 1/5 of a microsecond, so we use a value a little higher than that as
  31                 // our epsilon.
  32                 // To be clear, this error is introduced in our re-calculation of 'rounded'
  33                 // above in JavaScript.
  34                 if (Math.abs(rounded - x + expectedPrecision) < .0005) {
  35                  return true;
  36                 } else if (Math.abs(rounded - x) < .0005) {
  37                  return true;
  38                 }
  39
  40                  // Then we handle the case where you're sub-millisecond and the timer is not
  41                  // We check that the timer is not sub-millisecond by assuming it is not if it
  42                  // returns an even number of milliseconds
  43                  if (expectedPrecision < 1 && Math.round(x) == x) {
  44                    if (Math.round(rounded) == x) {
  45                      return true;
  46                    }
  47                  }
  48
  49                  ok(false, "Looming Test Failure, Additional Debugging Info: Expected Precision: " + expectedPrecision + " Measured Value: " + x +
  50                    " Rounded Vaue: " + rounded + " Fuzzy1: " + Math.abs(rounded - x + expectedPrecision) +
  51                    " Fuzzy 2: " + Math.abs(rounded - x));
  52
  53                  return false;
  54             };
  55
  56             var metrics = [
  57                 "unloadEventStart",
  58                 "unloadEventEnd",
  59                 "domInteractive",
  60                 "domContentLoadedEventStart",
  61                 "domContentLoadedEventEnd",
  62                 "domComplete",
  63                 "loadEventStart",
  64                 "loadEventEnd"
  65             ];
  66
  67             async function runTests(resistFingerprinting, reduceTimerPrecision, expectedPrecision) {
  68                 await SpecialPowers.pushPrefEnv({
  69                     "set": [["privacy.resistFingerprinting", resistFingerprinting],
  70                             ["privacy.reduceTimerPrecision", reduceTimerPrecision],
  71                             ["privacy.resistFingerprinting.reduceTimerPrecision.microseconds", expectedPrecision * 1000]
  72                 ]});
  73                 var entries = performance.getEntriesByType("navigation");
  74                 is(entries.length, 1, "Checking PerformanceNavigationEntry count");
  75
  76                 for (let i=0; i<entries.length; i++) {
  77                     for (let j=0; j<metrics.length; j++) {
  78                         ok(isRounded(entries[i][metrics[j]], reduceTimerPrecision, expectedPrecision),
  79                             "Testing " + metrics[j] + " with value " + entries[i][metrics[j]] +
  80                             " with resistFingerprinting " + resistFingerprinting + " reduceTimerPrecision " +
  81                             reduceTimerPrecision + " precision " + expectedPrecision);
  82                     }
  83                 }
  84             }
  85
  86             async function startTests() {
  87                 await runTests(false, false, 2);
  88                 await runTests(true, false, 2);
  89                 await runTests(true, true, 2);
  90                 await runTests(false, true, 1000);
  91                 await runTests(false, true, 133);
  92                 await runTests(false, true, 13);
  93                 await runTests(false, true, 2);
  94                 await runTests(false, true, 1);
  95
  96                 SimpleTest.finish();
  97             }
  98
  99             SimpleTest.waitForExplicitFinish();
 100             addLoadEvent(startTests);
 101             </script>
 102         </pre>
 103     </body>
 104 </html>