Adding TestUnit integration.

This should make sure everything works well with T::U.

Fixes #354.

lib/draper.rb

@@ -15,8 +15,9 @@ require 'draper/collection_decorator'
 require 'draper/railtie' if defined?(Rails)
 
 # Test Support
-require 'draper/test/rspec_integration'    if defined?(RSpec) and RSpec.respond_to?(:configure)
-require 'draper/test/minitest_integration' if defined?(MiniTest::Rails)
+require 'draper/test/rspec_integration'     if defined?(RSpec) and RSpec.respond_to?(:configure)
+require 'draper/test/minitest_integration'  if defined?(MiniTest::Rails)
+require 'draper/test/test_unit_integration'
 
 module Draper
   def self.setup_action_controller(base)

lib/draper/railtie.rb

@@ -40,5 +40,8 @@ module Draper
       Draper::ViewContext.build_view_context
     end
 
+    rake_tasks do
+      Dir[File.join(File.dirname(__FILE__),'tasks/*.rake')].each { |f| load f }
+    end
   end
 end

lib/draper/tasks/tu.rake

@@ -0,0 +1,3 @@
+Rake::Task["test:run"].enhance do
+  Rake::Task["test:decorators"].invoke
+end

lib/draper/test/test_unit_integration.rb

@@ -0,0 +1,9 @@
+require "rake/testtask"
+require "rails/test_unit/sub_test_task"
+
+namespace :test do
+  Rails::SubTestTask.new(:decorators => "test:prepare") do |t|
+    t.libs << "test"
+    t.pattern = "test/decorators/**/*_test.rb"
+  end
+end