rails/rails — pull request #7124 by grosser (2012-07-21 15:50:42+00:00)
Title: Make activemodel tests runnable without -Itest and from non-root folders

I try to make testing as easy as possible, which means for me that every test file should be runnable with `ruby pat/to/file_test.rb` from everywhere, which is also a requirement for a few editors, this failed in activemodel.
(I'll make more pull requests for the other rails parts if this one is accepted)