mozilla-central/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/timers.html

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Test Info: Warnings

<!doctype html>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="/common/dispatcher/dispatcher.js"></script>
<script src="resources/helper.sub.js"></script>
<script>
// Timers should be paused when the Document is not fully active.
// This test is checking this by measuring the actual elapsed time for a timer
// started before a page is stored into BFCache, staying for a while in BFCache,
// and fired after the page is restored from BFCache.
const delayMain = 18000;
const delayBeforeForwardNavigation = 6000;
const delayBeforeBackNavigation = 5000;
// `delayBeforeForwardNavigation` and `delayBeforeBackNavigation` are set
// sufficiently large in order to distinguish the expected case from other
// scenarios listed in `funcAfterAssertion()`, and to allow some delays outside
// timers (e.g. due to communication between Windows). The additional delays
// can be large (e.g. ~4 seconds), so the delays above should be sufficiently
// large.
const startTime = performance.now();
runBfcacheTest({
funcBeforeNavigation: async (delayMain, delayBeforeForwardNavigation) => {
// Set `promiseMainTimer` that is resolved after a timeout of `delayMain`
// ms.
window.promiseMainTimer = new Promise(resolve => {
setTimeout(resolve, delayMain);
});
// Then navigate to another page after `delayBeforeForwardNavigation` ms.
await new Promise(resolve =>
setTimeout(resolve, delayBeforeForwardNavigation));
},
argsBeforeNavigation: [delayMain, delayBeforeForwardNavigation],
funcBeforeBackNavigation: async (delayBeforeBackNavigation) => {
// Back navigate after `delayBeforeBackNavigation` ms.
await new Promise(resolve =>
setTimeout(resolve, delayBeforeBackNavigation));
},
argsBeforeBackNavigation: [delayBeforeBackNavigation],
funcAfterAssertion: async (pageA) => {
// Wait for `promiseMainTimer` resolution and check its timing.
await pageA.execute_script(() => window.promiseMainTimer);
const actualDelay = performance.now() - startTime;
if (actualDelay >= delayMain + delayBeforeBackNavigation +
delayBeforeForwardNavigation) {
assert_unreached(
"The timer is fired too late. " +
"Maybe the timer is reset when restored from BFCache and " +
"waits from the beginning again");
} else if (actualDelay >= delayMain + delayBeforeBackNavigation) {
// Expected: The timer is paused when the page is in BFCache.
} else if (actualDelay >= delayMain) {
assert_unreached(
"The timer is fired too early. " +
"Maybe the time isn't paused when the page is in BFCache");
} else {
assert_unreached(
"The timer is fired too early, even earlier than delayMain.");
}
}
}, 'Timers should be paused when the page is in BFCache');
</script>