Add automatic checks for html validation & accessibility

[svrnm]

Desired feature or idea.
I was looking into #1170 and #190 today and it reminded me of something I was playing around with for a different project a few months back:

• The Nu Html Checker, the tool behind https://validator.w3.org/nu/. It can be run on the command line (requires java or docker!) within npm run test to generate a report. The current report is extremely long but lots of issues come from templates that can be fixed together
• While not providing a perfect result, there are some tools to check for accessibility issues like Pa11y, others are mentioned at the Web Accessibility Evaluation Tool List. I choose pa11y because from a quick test it could also be integrated into npm run test

Is this something we want to have? Or is it adding to much complexity when people try to contribute (asking them to make sure that npm run test is not throwing errors anymore while be much harder then)

[chalin]

Thanks for the info about and link to the tools.

There are a number of checks that I'd like to add (currently at the top of my list is external links, #1052), but our focus has been on adding content so far -- and docsy-related work for me. As for the tools that you mention, I wouldn't consider adding them to CI checks, but it might make sense to consider using them now and again. My 2 cents.

[svrnm]

As for the tools that you mention, I wouldn't consider adding them to CI checks, but it might make sense to consider using them now and again. My 2 cents.

I am fully OK with that, there are plenty of errors, you might not want to fix right now, some false positives, some things you just have to live with etc, so let me find some time to run them over some packages and report back some results.