How to Test Polymer/Webcomponent
Copado Recorder does its best to record / analyze the actions taken in the browser, but some actions are simply outside the standards. In this case, the only workaround is to right-click an element, add it to the Copado Recorder and edit the command and value columns to some suitable action.
When you do right click and select Add element to Copado Recorder, this element is added to the Recorder with "assertElementPresent" as a command. The locator will depend on the element selected: