<!DOCTYPE html>
<html>
<body>
<p>You should see PASS below:</p>
<div><span></span></div>
<script>

var host = document.querySelector('div');
var root = host.attachShadow({mode: 'open'});
root.appendChild(document.createElement('slot'));

if (window.testRunner)
    testRunner.waitUntilDone();

setTimeout(function () {
    var b = document.createElement('b');
    b.innerHTML = 'PASS';
    document.querySelector('span').appendChild(b);
    testRunner.notifyDone();
}, 0);

</script>
</body>
</html>