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.
<youtube-list-embed-lit-element
width="100%"
height="500px"
listid="PL32HFpx_LBMvvsDUTEBQxIdrmszkfEM0H"
></youtube-list-embed-lit-element>
$ 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.