{opacity: '0.25', left: '0px'},
    0.25: {opacity: '0.25', left: '12.5px'},
    0.5: {opacity: '0.5', left: '25px'},
    0.75: {opacity: '0.5', left: '37.5px'},
    1: {opacity: '0.5', left: '50px'},
  });
},
'element.animate() with eased keyframe on single property',
{
  help: 'http://dev.w3.org/fxtf/web-animations/#the-keyframe-dictionary',
  assert: [
    'element.animate() should start an animation when keyframes are specified with timing functions',
    'for their easing property. The animation should