Rails 3.2 - test for application_helper.rb fails when trying to access application_controller method

I am trying to test my application_helper methods, and some of them are calling ApplicationController methods

class ApplicationHelperTest < Test::Unit::TestCase

test ‘test_copyrights’ do

assert_equal @subdomain[:name], copyright


class ApplicationController < ActionController::Base

helper_method :current_subdomain

def current_subdomain



but the test is failing :

NameError: undefined local variable or method `current_subdomain’

how can I test it ? ( where… in unit/functional/integration test ? and how to access the ApplicationController methods ?)

thanks for feedback