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<!DOCTYPE HTML>
<html>
<!--
-->
<head>
<meta charset="utf-8">
<title>Test for Bug 1478519</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
</head>
<body>
<p id="display"></p>
<div id="content" style="display: none">
</div>
<pre id="test">
</pre>
<script>
'use strict';
async function waitForFrame() {
return new Promise(resolve => {
window.requestAnimationFrame(resolve);
});
}
// Returns a Promise which will be resolved when the 'change' event is received
// for the given media query string.
async function promiseForChange(mediaQuery) {
return new Promise(resolve => {
window.matchMedia(mediaQuery).addEventListener('change', event => {
resolve(event.matches);
}, { once: true });
});
}
add_task(async () => {
const initiallyMatches =
window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const changePromise = initiallyMatches ? promiseForChange('(prefers-reduced-motion: reduce)') : null;
await SpecialPowers.pushPrefEnv({ set: [['ui.prefersReducedMotion', 0]]});
if (changePromise) {
await changePromise;
}
ok(!window.matchMedia('(prefers-reduced-motion: reduce)').matches,
'Does not matches prefers-reduced-motion: reduced) when the system sets ' +
'prefers-reduced-motion false');
ok(!window.matchMedia('(prefers-reduced-motion)').matches,
'Does not matches (prefers-reduced-motion) when the system sets ' +
'prefers-reduced-motion false');
ok(window.matchMedia('(prefers-reduced-motion: no-preference)').matches,
'Matches (prefers-reduced-motion: no-preference) when the system sets ' +
'prefers-reduced-motion false');
});
add_task(async () => {
const reduce = promiseForChange('(prefers-reduced-motion: reduce)');
const booleanContext = promiseForChange('(prefers-reduced-motion)');
const noPreference = promiseForChange('(prefers-reduced-motion: no-preference)');
await SpecialPowers.pushPrefEnv({ set: [['ui.prefersReducedMotion', 1]]});
const [ reduceResult, booleanContextResult, noPreferenceResult ] =
await Promise.all([ reduce, booleanContext, noPreference ]);
ok(reduceResult,
'Matches (prefers-reduced-motion: reduced) when the system sets ' +
'prefers-reduced-motion true');
ok(booleanContextResult,
'Matches (prefers-reduced-motion) when the system sets ' +
'prefers-reduced-motion true');
ok(!noPreferenceResult,
'Does not matches (prefers-reduced-motion: no-preference) when the ' +
'system sets prefers-reduced-motion true');
await SpecialPowers.flushPrefEnv();
});
</script>
</body>
</html>