UploadWizard tests fail on the new messages structure test ResourcesTest::testMissingMessages() (39a00e2e) due to loading messages from WikimediaMessages. Example failing change (that should be passing): https://gerrit.wikimedia.org/r/305272 → https://integration.wikimedia.org/ci/job/mwext-testextension-hhvm/21204/console
The messages are not actually used by the code in the default configuration, so this is not a bug; they are used in WMF's configuration though (and we can't easily make the list of loaded messages dynamic).
I think it's possible to specify somewhere in CI config that UploadWizard depends on WikimediaMessages, but I don't remember where. Please help :)