Wt

Recently there was an error with an implementation (#12006, fixed in #12143). This caused a JS error to be logged if a WPaintedWidget was present on the page.
This issue could have been caught in the widget gallery, if the right page had been opened.

We can for each feature of course open each page of the widget gallery. Doing this manually for each ticket would be a waste of time. We can automate this, for example using Selenium.
While Selenium is capable of much more, and a smaller test would suffice, we can start to introduce Selenium already, so that later on more complex examples can be added.

For now it will suffice to open each page of the widget gallery, and check that no JS errors have occurred.

Later we can start doing some more integrated example, like interacting with the page by providing input, and checking its output.