  return animation.ready.then(waitForAnimationFrames(1)).then(() => {
    assert_true(animation.currentTime >= previousCurrentTime,
                'currentTime is initially increasing');
    animation.pause();
    return animation.ready;
  }).then(() => {
    previousCurrentTime = animation.currentTime;
    return waitForAnimationFrames(1);
  }).then(() => {
    assert_equals(animation.currentTime, previousCurrentTime,
                  'currentTime does not increase after calling pause()');
  });
}, 'paus