This fab enters after page has been scrolled a bit, smoothly scrolls window back to top when clicked
First, make sure you have the Polymer CLI and npm (packaged with Node.js) installed. Run npm install to install your element's dependencies, then run polymer serve to serve your element locally.
$ polymer serve
$ polymer test
Your application is already set up to be tested via web-component-tester. Run polymer test to run your application's test suite locally.