One team discovered a jaw-dropping issue with has_many :through. Given the following:
class User < ActiveRecord::Base has_many :user_photos has_many :photos, :through => :user_photos
a_user.photos.createwill create and persist both a Photo object and the UserPhoto join object
photo = a_user.photos.buildfollowed by
photo.savewill create and persist the Photo object only, and will not persist an appropriate UserPhoto join object.
Test::Unit::TestCaseextentions have been removed from Rails Core and are now in
ActiveSupport::TestCase. As stated in the Groups Thread about this, use