ll, 'null');
    assert_equals(cues.getCueById(undefined), null, 'undefined');
}, document.title+ ', no id');
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');
    c.id = 'foo';
    t.addCue(c);
    assert_equals(cues.getCueById(""), null, '""');
    assert_equals(cues.getCueById("foo"), c, '"foo"');
    assert_equals(cues.getCueById({toString:funct