<!DOCTYPE html>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>

<script>
test(function() {
  document.timeline.playbackRate = 0;
  document.timeline.currentTime = 0;
  var player = document.documentElement.animate([], 1000);
  player.startTime = -1000;

  assert_equals(player.currentTime, 1000);

  player.effect.timing.duration = 1500;
  document.timeline.currentTime = 2000;

  assert_equals(player.startTime, -1000);
  assert_equals(player.currentTime, 1500);
}, 'Extending effect should not cause a change in start time.');
</script>