Role Rules from the ARIA Spec (Fallback Role, Host Language Conflict, Invalid and Abstract Roles, etc.)

[cookiecrook]

I plan to start working on role rules from the ARIA spec... in wpt/wai-aria/role… Here's the general plan:

I'll include a ReadMe that points the implicit role mappings (e.g. <main> -> "main") should be in the spec folder for each host language mapping spec, like wpt/html-aam.

I'll add several files that test things like:

• the simple explicit role mappings for all defined core ARIA roles... e.g. <div role="group"> -> "group" (note: this will be a single big file in mostly alphabetical order by role name, but will not include edge or error cases)
• fallback role tests role="switch checkbox" role="foo checkbox" role="checkbox foo"
• invalid roles role="foo" including abstract roles role="widget"
• contextual role invalidations like orphaned roles outside their required context like a cell outside a table <div role="cell"> -> "undefined" (the resulting roles may be underspecified in some cases, so there may be implementation differences)
• Other error or edge cases as I think of them. I'll probably review all the RFC MUST and MUST NOT statements for UAs in the ARIA spec, and discuss with other ARIA WG members along the way.

[cookiecrook]

@jnurthen @spectranaut are there other obvious error case patterns or categories of core role testing I missed? thx