anchor.diff:        var setSize = 100;
         list.items = buildDataSet(setSize);
         setSize = list.items.length;
  +      // TODO(jakemac): Update once we resolve
  +      // https://github.com/dart-lang/polymer_interop/issues/6
         list.jsElement.callMethod('push', ['items', buildItem(setSize)]);
         expect(list.items.length, setSize + 1);
         new Future(() {}).then((_) {
  
positive.code:       var setSize = 45;
        var phrase = 'It works!';
        list.items = buildDataSet(setSize);
        list.jsElement.callMethod(
            'splice', ['items', 0, setSize, buildItem(phrase)]);
        return new Future(() {}).then((_) {
  
negative.code:         }, ([_]) {
            var viewportHeight = list.offsetHeight;
            var itemsPerViewport = (viewportHeight / rowHeight).floor();
            // TODO(jakemac): Update once we resolve
            // https://github.com/dart-lang/polymer_interop/issues/6
            list.jsElement.callMethod('pop', ['items']);
            new Future(() {}).then((_) {
              expect(list.items.length, setSize-1);
  