<!doctype html>
<title>TextTrackCueList.getCueById</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<div id=log></div>
<script>
test(function(){
    var video = document.createElement('video');
    var t = video.addTextTrack('subtitles');
    document.body.appendChild(video);
    var cues = t.cues;
    var c = new VTTCue(0, 1, 'text1');
    t.addCue(c);
    assert_equals(cues.getCueById(""), null, '""');
    assert_equals(cues.getCueById(null), nu