Changeset [83be262b4b2e415fe9be319eb6b187bcf415fb6d] by Carlhuda

Isolation tests intentionally avoid loading any state (because they're often testing things that have their own load path semantics that should not be polluted), so rack/test is not yet on the load path. Moving require "rack/test" into the setup means and after boot_rails means that it'll be required after the laod path has been altered to add in the Rails vendor/gems
http://github.com/rails/rails/commit/83be262b4b2e415fe9be319eb6b187...