page-visibility/minimize.html

<!DOCTYPE HTML>
<title>Test different scenarios of how browser interactions are reflected by page visibility</title>
<link rel="author" title="Noam Rosenthal"  href="mailto:noam@webkit.org">
<link rel="help" href="https://www.w3.org/TR/page-visibility-2/">
<meta name="timeout" content="long">
<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>

const iframePath = 'resources/blank_page_green.html'

function window_state_context(t) {
    let rect = null
    const restore = () => test_driver.set_window_rect(rect);

    return {
        minimize: async () => {
            if (rect === null)
                t.add_cleanup(restore)

            rect = await test_driver.minimize_window()
        },

        restore
    }
}

promise_test(async t => {
    const {minimize, restore} = window_state_context(t);
    assert_equals(document.visibilityState, "visible");
    assert_equals(document.hidden, false);
    await minimize();
    assert_equals(document.visibilityState, "hidden");
    assert_equals(document.hidden, true);
    await restore()
    assert_equals(document.visibilityState, "visible");
    assert_equals(document.hidden, false);
}, "visibilityState & hidden should be affected by window being minimized/restored");

promise_test(async t => {
    const {minimize, restore} = window_state_context(t);
    const events = [];
    const callback = () => events.push(document.visibilityState);
    document.addEventListener('visibilitychange', callback);
    t.add_cleanup(() => document.removeEventListener('visibilitychange', callback));
    await minimize();
    await restore();
    assert_array_equals(events, ['hidden', 'visible']);
}, "visibilitychange event should be fired when minimized/restored")

promise_test(async t => {
    const {minimize, restore} = window_state_context(t);
    const events = [];
    const iframe = document.createElement('iframe');
    iframe.src = iframePath;
    document.body.appendChild(iframe);
    t.add_cleanup(() => iframe.remove());
    await new Promise(resolve => iframe.onload = resolve);
    const callback = () => events.push(iframe.contentWindow.document.visibilityState);
    iframe.contentWindow.addEventListener('visibilitychange', callback);
    await minimize();
    await restore();
    iframe.contentWindow.removeEventListener('visibilitychange', callback);
    assert_array_equals(events, ['hidden', 'visible']);
}, "iframe should receive visibility events when top level window is shown/hidden");
</script>