Updated yaffle_test.rb from 2.2 to require 'test_helper' and extend ActiveSupport::TestCase

railties/guides/source/plugins.textile

@@ -220,9 +220,9 @@ Once you have these files in place, you can write your first test to ensure that
 <ruby>
 # vendor/plugins/yaffle/test/yaffle_test.rb
 
-require File.dirname(__FILE__) + '/test_helper'
+require 'test_helper'
 
-class YaffleTest < Test::Unit::TestCase
+class YaffleTest < ActiveSupport::TestCase
   load_schema
 
   class Hickwall < ActiveRecord::Base