This will blow up if someone includes a module with public methods that would count as actions.

# application_controller_test.rb
class ApplicationControllerTest < ActionController::TestCase
  class CleanController < ApplicationController
  end

  test "should be clean" do
    assert_equal [], CleanController.action_methods.to_a.
      reject{|a| a =~ /^_conditional_callback_around_/}
  end
end