Development Blog: Viget Labs

The conventional approach to testing helpers in Rails has, until recently, always been relatively subjective. I have come across different strategies including generators, plugins and hand-hacked setups depending on where I looked. In sharp contrast, the controller testing convention has been DRY'd up and moved into the framework in the form of the ActionController::TestCase class. Fortunately, Brian has been working on some helper testing tools and recently stumbled across the ActionView::TestCase class. If you have been looking for a convenient, framework supported way to test your helpers, look no further. This class provides the same conventions as ActionController::TestCase and makes testing helpers a breeze.

Test Your Helpers Using ActionView::TestCase
Here is an example that shows how to use ActionView::TestCase along with Brian's assert_tag_in. First, create a test named HelperNameTest and inherit from ActionView::TestCase. Then just call your helper methods from your tests, it's that easy.

module ApplicationHelper
  def special_header()
    content_tag :div do
      link_to('Edit Profile', edit_account_path)
    end
  end
end

class ApplicationHelperTest < ActionView::TestCase
  def test_special_header_should_render_edit_link
    tag = special_header(:edit_profile => true)
    assert_tag_in(tag, :a, :attributes => {:href => edit_account_path})
  end
end

Worth noting here is the ability to test methods that rely on url_for without needing to create a temporary controller in your own testing code. I also want to point out that Chu Yeow did cover using ActionView::TestCase in his Living on the Edge series, but it totally slipped past me :)

Update

ActionView::TestCase is not loaded automatically. Be sure to require 'action_view/test_case' in your test_helper.