Source code

Revision control

Copy as Markdown

Other Tools

Test Info:

<!DOCTYPE html>
<meta charset=utf-8 />
<meta name="timeout" content="long">
<title>Event Timing: eventCounts.</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script src=/resources/testdriver.js></script>
<script src=/resources/testdriver-vendor.js></script>
<script src=/resources/testdriver-actions.js></script>
<script src=/page-visibility/resources/window_state_context.js></script>
<script src=resources/event-timing-test-utils.js></script>
<button id='target'>Click me</button>
let observedEntries = [];
const map = new Map();
const events = ['pointerdown'];
promise_test(async t => {
assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
const { minimize, restore } = window_state_context(t);
const button = document.getElementById('target');
const callback = (entryList) => { observedEntries = observedEntries.concat(entryList.getEntries().filter(filterAndAddToMap(events, map))); };
const readyToResolve = () => { return observedEntries.length >= 1; };
const observerPromise = createPerformanceObserverPromise(['event'], callback, readyToResolve);
const tapEventPromise = new Promise(resolve => {
button.addEventListener('pointerdown', async (event) => {
document.body.innerText += "Adding content to force rendering";
// await here will yield to event loop, and end event processing time,
// which will allow rendering to continue.
// The visibility change may happen before rendering has a chance
// but it is not guarenteed which will happen first.
await minimize();
const timeAfterVisibilityFalse =;
await restore();
const timeAfterVisibilityTrue =;
resolve({ timeAfterVisibilityFalse, timeAfterVisibilityTrue });
// A buffered visibility-state PerformanceEntry would have made this test
// cleaner, due to the variability of ordering of events, but it is not
// yet available.
const visibilityEventPromise = new Promise(resolve => {
document.addEventListener('visibilitychange', (event) => {
if (document.visibilityState !== 'visible') {
const timeBeforeTap =;
await interactAndObserve('tap', button, observerPromise);
// The order that these events fire is non-deterministic, but we can await
// the result of the promise in any order.
const { timeAfterVisibilityFalse, timeAfterVisibilityTrue } = await tapEventPromise;
const timeOfVisibilityFalse = await visibilityEventPromise;
assert_equals(observedEntries.length, 1, "Pointerdown was measured");
const entry = observedEntries[0];
assert_not_equals(timeBeforeTap, undefined);
assert_not_equals(timeAfterVisibilityFalse, undefined);
assert_not_equals(timeAfterVisibilityTrue, undefined);
assert_not_equals(timeOfVisibilityFalse, undefined);
"event handler ends before visibility event fires"
"visibility event fires before event handler continues"
entry.startTime + entry.duration,
"event duration ends before visibility is changed"
}, "Event handlers which change visibility should not measure next paint.");