<script>
var tests = [
  'test-change-playback-rate.html',
  'test-composite-transforms.html',
  'test-compositor.html',
  'test-fill-values.html',
  'test-iterations-basic.html',
  'test-iterations-fill-declarative.html',
  'test-iterations-fill.html',
  'test-iteration-start.html',
  'test-keyframe-creation.html',
  'test-pause.html',
  'test-playback-rate.html',
  'test-seq-speed.html',
  'test-svg-anim.html',
  'test-templating.html',
  'test-timing-functions.html',
  'test-to-animation.html',
];
</script>
<style>
iframe {
  width: 800px;
  height: 600px;
}
</style>
<button id=prev-button onclick="updateState(-1)">Prev</button>
<button id=reload-button onclick="updateState()">Reload</button>
<button id=next-button onclick="updateState(1)">Next</button><br>
<div id=test-name></div>
<iframe></iframe>
<script>
var currentTest = 0;

function updateState(change) {
  if (change) {
    currentTest += change;
  }
  var test = tests[currentTest];
  document.querySelector('#test-name').innerText = (currentTest + 1) + ' of ' + tests.length + ': ' + test;
  document.querySelector('iframe').src = test;
  document.querySelector('#prev-button').disabled = currentTest <= 0;
  document.querySelector('#next-button').disabled = currentTest >= tests.length - 1;
}

updateState();
</script>

Add a manual test harness.
Add a manual test harness.
