longtask-timing/longtask-in-externalscript.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>LongTask Timing: long task in external script</title>
<body>

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/utils.js"></script>

<h1>Long Task: External Script</h1>
<div id="log"></div>
<script>
promise_test(function(t) {
  assert_implements(window.PerformanceLongTaskTiming, 'Longtasks are not supported.');
  const performanceObserverTimeout = 5 * 1000;
  const longTasksPromise = new Promise(resolve => {
    const observer = new PerformanceObserver(
      t.step_func(function(entryList) {
        const entries = entryList.getEntries();
        entries.forEach(longtask => {
          assert_equals(longtask.entryType, 'longtask');
          if (hasUnrelatedTaskName(longtask.name, 'self')) {
            return;
          }
          checkLongTaskEntry(longtask);
          // Assert the TaskAttributionTiming entry in attribution.
          assert_equals(longtask.attribution.length, 1,
            'Exactly one attribution entry is expected');
          const attribution = longtask.attribution[0];
          assert_equals(attribution.entryType, 'taskattribution');
          assert_equals(attribution.name, 'unknown');
          assert_equals(attribution.duration, 0);
          assert_equals(attribution.startTime, 0);
          assert_equals(attribution.containerType, 'window');
          assert_equals(attribution.containerId, '');
          assert_equals(attribution.containerName, '');
          assert_equals(attribution.containerSrc, '');
          observer.disconnect();
          resolve();
        })
      }));
    observer.observe({
      entryTypes: ['longtask']
    });
    const script = document.createElement('script');
    script.src = 'resources/makelongtask.js';
    document.body.appendChild(script);
  });
  const timeout = new Promise(
    (resolve, reject) => t.step_timeout(
      () => {
        reject(new Error('observer failed to find any entries'))
      },
      performanceObserverTimeout)
  )
  return Promise.race([longTasksPromise, timeout]);
}, 'Performance longtask entries are observable.');
</script>
</body>