Add HTML_CodeSniffer as an ACT implementation for W3C

[WilcoFiers]

I was wondering if it HTML_CodeSniffer community would be interested to see this tool added to the W3C's list of ACT implementations. This is a list of test tools and methodologies that test for WCAG 2 and/or ARIA.

In summary, the Accessibility Conformance Testing (ACT) project is a W3C effort to try and reduce inconsistencies between, and improve transparency of accessibility testers. To accomplish this, the W3C has created various rules that define how to apply WCAG success criteria to HTML, CSS and ARIA. Each rule comes with a number of examples / test cases, that can be used to determine whether different tools / testing solutions get the results expected from the rule.

Since HTML CS is an important and heavily used tool for accessibility testing, I think having it on the list would be great. This will help give insight into the capabilities of HTML_CodeSniffer. What kinds of things does it find; and what doesn't it find. This is also useful for future development of HTML CS, by giving examples for cases that HTML CS hasn't covered yet.

I created a preview of what this might look like for HTML_CodeSniffer. This was done by running HTML CS against the 1000+ test cases ACT has, and programmatically comparing the results to the expected results. Please note this is not live, nor will this be indexed. https://deploy-preview-176--wai-wcag-act-rules.netlify.app/standards-guidelines/act/implementations/htmlcs/

Some things of note:

• The "Rule name" are taken from the ACT rules. Rules in HTML-CS are called "procedures" in this page.
• Rules where HTML CS fails something that ACT says should pass are not included.
• I simplified the HTML CS rule IDs a bit, stripping out the level, principle, and guideline portion. This was done just to have them fit the page better.
• HTML CS warnings are reported as "cannot tell". This is a standard term used for when an automated tool suspects a problem but isn't certain.
• HTML CS notices are not considered, although they could be

Additional resources:

• About ACT Rules
• List of all ACT Rules
• List of all ACT current implementations
• Source which generated the ACT report for HTML CS

Lastly, if the HTML CS community is not interested I can easily remove these pages. I don't think there is anything sensitive in the work I did, but if there is let me know.

[mgifford]

Aligning with the W3C's ACT Rules would be a big plus for htmlcs!