This is a followup of MDL-49418 where a regression was fixed, related with some changes to require_login().

Such a function is so complex, has so many related implications, chained dependencies... that we should try to provide some extra acceptance tests verifying different aspects that may become broken in the future.

Of course, ideally, the function should not lead to all those chained dependencies (say modinfo, availability, theme, page, context...) and both MDL-49434 and MDL-41809 are basically about that.

This is just to ensure some behaviors won't break with future modifications of such a central function.

Ideas are welcome, indeed.