t to the effect end');

  return animation.ready.then(() => {
    assert_equals(animation.currentTime, 1000 * MS_PER_SEC,
                  'keeps the initially set currentTime');
  });
}, 'pause() from idle with a negative playbackRate');

test(t => {
  const div = createDiv(t);
  const animation = div.animate({}, {duration: 1000 * MS_PER_SEC,
                                   iterations: Infinity});
  animation.cancel();
  animation.playbackRate = -1;

  assert_throws_dom('InvalidStateError',
           