Bug 1486094 makes path() animatable, but its wpt are in `css/motion/animation`. We should move its WPT to `property-list.js` [1] by adding a generic path type. Then we can test addition or others in the future. (It seems the addition of path() is not defined in SVG and CSS shape 2 spec. Maybe we could make it defined in web animation spec later. https://drafts.csswg.org/web-animations/#animation-types) Besides, we should also fill opacity in property-list.js [1]. [1] web-animations/animation-model/animation-types/property-list.js

Thanks for filing this. Ultimately this should probably be defined in either SVG or some generic spec like V&U and then the tests should move there. In fact, the whole property-list.js setup should move to V&U for the animation types we end up specifying there. For now, simply filling in `opacity` etc. would be a good idea so that we have test coverage of that.