Challenge! How can I write a test to test the methods in ApplicationController?

Hi all,

I've been Googling this one for a while now, and haven't found a
satisfactory answer. It has been posted here before by someone else,
but it seems to have got forgotten, so here goes - perhaps someone can
think up a way around the problem?

In ApplicationController, I have the following method:

class ApplicationController < ActionController::Base

<snip>

  helper_method :admin?

  # Discover whether the currently logged user is an admin user
  def admin?
    User.find_by_id(session[:user_id]).admin? unless
session[:user_id].nil?
  end
<snip>

This method works fine in various views, but I can't seem to test it.
Rails doesn't generate a test file for ApplicationController, so I
have done that:

require File.dirname(__FILE__) + '/../test_helper'
require 'application.rb'

# Re-raise errors caught by the controller.
class ApplicationController; def rescue_action(e) raise e end; end

class ApplicationControllerTest < Test::Unit::TestCase
  fixtures :users

  def logger
    RAILS_DEFAULT_LOGGER
  end

  def setup
    @controller = ApplicationController.new
    @request = ActionController::TestRequest.new
    @response = ActionController::TestResponse.new

  end

  def test_admin
    # Don't know how to test "admin?"
  assert false
  end

end

I can run this test successfully, but if I include a call to admin?, I
get a NoMethodError. I also get the same thing if I try testing it in
another controller (which inherits from application.rb).

Any ideas?

Cheers,

Henry