Hello,
After much hassle with Jenkins, ant and PHPUnit, I finally managed to run an extension PHPUnit test suite under Jenkins.
The winner is TitleBlacklist for which results are available via: https://integration.mediawiki.org/ci/job/Ext-TitleBlacklist/
The Jenkins job is setup to report the build status back in Gerrit.
If you see any issue, please fill in a bug under Testing infrastructure.
TODO: Job does not run PHP lint yet.