There are issues running Mongo/mongoid whatever on Rubinius, which I hope to be able to fix soon, but the changes to testing on Rubinius are correct if you want to merge now.
Coverage decreased (-16.74%) to 79.37% when pulling 71aa3158dcf2277f76a3f4d2687ae9799b4852cc on brixen:master into 2a5eea17ddbc8f06e2f66b390fff39857baed7b2 on collectiveidea:master.
There are issues running Mongo/mongoid whatever on Rubinius, which I hope to be able to fix soon, but the changes to testing on Rubinius are correct if you want to merge now.