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<!DOCTYPE html>
<meta charset="utf-8">
<title>Monitoring the list of available presentation displays.</title>
<link rel="help" href="http://w3c.github.io/presentation-api/#monitoring-the-list-of-available-presentation-displays">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="common.js"></script>
<p id="notice">Please wait for a moment...</p>
<p>The test passes if a "PASS" result appears.<br></p>
<script>
// prevent the default timeout
setup({explicit_timeout: true});
const notice = document.getElementById('notice');
promise_test(t => {
// clean up the instruction notice when the test ends
t.add_cleanup(() => {
notice.parentNode.removeChild(notice);
});
// initialize a presentation request
const request = new PresentationRequest(presentationUrls);
let availability, previousState, timeout;
const wait = () => {
notice.textContent = 'Please wait for a moment... (It might take long time)';
// set timeout to observe the presentation availability
timeout = t.step_timeout(function() {
t.force_timeout();
t.done();
}, 90000);
};
const setup = () => {
// save the current value of the presentation availability
previousState = availability.value;
// show an instruction notice
notice.textContent = 'Please make your presentation displays '
+ (previousState ? 'unavailable' : 'available')
+ ' and click this button: ';
const button = document.createElement('button');
button.textContent = 'Start Monitoring';
button.onclick = wait;
notice.appendChild(button);
};
// check the event and its attributes
const checkEvent = evt => {
clearTimeout(timeout);
timeout = undefined;
assert_true(evt.isTrusted && !evt.bubbles && !evt.cancelable && evt instanceof Event, 'A simple event is fired.');
assert_equals(evt.type, 'change', 'The event name is "change".');
assert_equals(evt.target, availability, 'event.target is the presentation availability.');
assert_not_equals(previousState, availability.value, 'Value of the presentation availability is changed.');
setup();
};
const watchEvent = (obj, watcher, type) => {
const watchHandler = new Promise(resolve => {
obj['on' + type] = evt => { resolve(evt); };
});
return Promise.all([ watchHandler, watcher.wait_for(type) ]).then(results => {
assert_equals(results[0], results[1], 'Both on' + type + ' and addEventListener pass the same event object.');
return results[0];
});
};
// check the change of PresentationAvailability.value twice; "true to false" and "false to true"
return request.getAvailability().then(a => {
availability = a;
setup();
// wait until a "change" event is fired twice
var eventWatcher = new EventWatcher(t, availability, 'change');
return watchEvent(availability, eventWatcher, 'change')
.then(checkEvent)
.then(() => { return eventWatcher.wait_for('change'); })
.then(checkEvent);
});
});
</script>