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<!--
https://bugzilla.mozilla.org/show_bug.cgi?id=1252268
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<meta charset="utf-8">
<title>Test for Bug 1378394</title>
<script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
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<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1378394">Mozilla Bug 1378394</a>
<script>
SimpleTest.waitForExplicitFinish();
// Some of our platforms are quite slow. Use very large time values to
// try to avoid raciness.
const burnTimeMS = 5000;
const intervalTimeMS = 10000;
// The overall interval should include our callback "burn time". So we
// expect the delay to be the remaining time.
const expectedDelayMS = intervalTimeMS - burnTimeMS;
// Allow some margin for error because of slow test platforms.
const allowedMarginMS = burnTimeMS / 2;
let id;
let lastEndTime;
function interval()
{
let start = performance.now();
if (lastEndTime !== undefined) {
let delta = start - lastEndTime;
ok(delta <= expectedDelayMS + allowedMarginMS,
'interval should not fire too late');
ok(delta >= expectedDelayMS - allowedMarginMS,
'interval should not fire too early');
clearInterval(id);
SimpleTest.finish();
return;
}
while((performance.now() - start) < burnTimeMS);
lastEndTime = performance.now();
}
id = setInterval(interval, intervalTimeMS);
</script>
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