NullDB, for those who don’t know, is a null backend for ActiveRecord. Unlike RSpec’s stub_object, rather than raise an exception on DB access, will NullDB DB interactions simply become no-ops. This is handy for things like testing after_save hooks in isolation.
Myron Marston has done a stellar job shepherding it through the Rails 3 transition, but he’s busy with other awesome projects now and has asked me to look for a new maintainer. So: If you’re interested in helping keep NullDB up to date with the latest changes to ActiveRecord, please get in touch!