The tests below should work on the MVP, so they must not require variables. So no login.
For MediaWiki, relevant stories to test are:
* fixture that consists of a page with two revisions
* anonymous page creation and editing, verify change in content (verifying access to old revisions requires variable support) via [[API:Edit]]
* re-parse of dependent pages (red links turning blue, missing templates getting used after being created) via [[API:Edit]] and then fetching the rendered page from the article path (index.php?title=xyz)
* page history with edit summary, size diff (testing minor edits and user names requires variables for login) see [[API:Revisions]]
* recent changes with edit summary, size diff, etc [[API:RecentChanges]]
* renaming/moving a page (basic) via [[API:Move]]
* pre-save transform (PSR) (via [[API:Edit]])
* [[Help:Templates|template transclusion]] via [[API:Parsing wikitext]]
* [[Help:Magic_words#Parser_functions|parser functions]] via [[API:Parsing wikitext]] (some)
* [[Help:Magic_words#variables|magic words]] via [[API:Parsing wikitext]] (some)
* diffs (use relative revision ids) via [[API:Compare]]
* fetching different kinds of links / reverse links (see [[API:Query#Page_types]])
* listing category contents (see [[API:Query#Page_types]])
In addition, it would be useful to see one or two basic tests for Kask and RESTbase.
It would be nice to see what these tests look like in our own runner (phester) and for some of the other candidates like tavern, behat, codeception, or dredd. It's not necessary to write all the tests for all the different systems, though.