I think that 2.6.0 was supposed to help with Rails 2.0.2 compatibility, however, it's still doesn't work out of the
box.

register_default_template_handler and register_template_handler are not in class ActionView::Base, they are in class
ActionView::Template so the code at rails_helper.rb:159 fails.

Swapping "Base" with "Template" seems to fix things up properly.