longtask-attributes.html
<!DOCTYPE HTML>
<meta charset=utf-8>
<title>LongTask Timing: validate long task attributes</title>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<h1>Long Task Attributes</h1>
<div id="log"></div>
<script>
async_test(function (t) {
const observer = new PerformanceObserver(
t.step_func(function (entryList) {
const entries = entryList.getEntries();
assert_equals(entries.length, 1,
'Exactly one entry is expected.');
const longtask = entries[0];
assert_equals(longtask.entryType, 'longtask');
assert_equals(longtask.name, 'self');
assert_greater_than(longtask.duration, 50);
assert_greater_than_equal(longtask.startTime, 0);
const currentTime = performance.now();
assert_less_than_equal(longtask.startTime, currentTime);
// 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, 'script');
assert_equals(attribution.duration, 0);
assert_equals(attribution.startTime, 0);
assert_equals(attribution.containerId, '');
assert_equals(attribution.containerName, '');
assert_equals(attribution.containerSrc, '');
observer.disconnect();
t.done();
})
);
observer.observe({entryTypes: ['longtask']});
/* Generate a slow task */
const begin = window.performance.now();
while (window.performance.now() < begin + 51);
}, 'Performance longtask entries are observable.');
</script>
</body>