#<firefly-security>
This mixin makes it possible to get the custom claims for the user. This mixin must be used on a page that has a 'firebase-auth' element.
First, make sure you have the Polymer CLI installed. 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.