To test out automatic MediaWiki release, we would need a MySQL database setup on a per job / per build basis.
To achieve that, a shell sript needs to be written that would use a jenkins user having create database / create user rights. The script would take in parameter a database name, user and password to create, that can later on be used by the Job to initialize the database and run tests with it.
This is a blocker for automatic MediaWiki release and will let us run unit tests using a MySQL database in addition to Sqlite backed tests.
So, that is quite important :-] Have been requested for mw/core PHPunit testing in bug 35912.