path: root/railties/doc/guides/source/creating_plugins/helpers.txt

== Add a helper ==

This section describes how to add a helper named 'WoodpeckersHelper' to your plugin that will behave the same as a helper in your main app.  This is very similar to adding a model and a controller.

You can test your plugin's helper as you would test any other helper:

*vendor/plugins/yaffle/test/woodpeckers_helper_test.rb*

[source, ruby]
---------------------------------------------------------------
require File.dirname(__FILE__) + '/test_helper.rb'
include WoodpeckersHelper

class WoodpeckersHelperTest < Test::Unit::TestCase
  def test_tweet
    assert_equal "Tweet! Hello", tweet("Hello")
  end
end
---------------------------------------------------------------

This is just a simple test to make sure the helper is being loaded correctly.  After watching it fail with `rake`, you can make it pass like so:

*vendor/plugins/yaffle/lib/yaffle.rb:*

[source, ruby]
----------------------------------------------
%w{ models controllers helpers }.each do |dir|
  path = File.join(File.dirname(__FILE__), 'app', dir)
  $LOAD_PATH << path
  ActiveSupport::Dependencies.load_paths << path
  ActiveSupport::Dependencies.load_once_paths.delete(path)
end

ActionView::Base.send :include, WoodpeckersHelper
----------------------------------------------


*vendor/plugins/yaffle/lib/app/helpers/woodpeckers_helper.rb:*

[source, ruby]
----------------------------------------------
module WoodpeckersHelper
  
  def tweet(text)
    "Tweet! #{text}"
  end
  
end
----------------------------------------------

Now your test should be passing, and you should be able to use the Woodpeckers helper in your app.