A spec for a filter

privacy_filter.rb

class PrivacyFilter
  class << self 
    def filter(controller)
      @controller = controller

      first_article? or administrator? or user?
    end
    
    def first_article?
      @controller.params[:id] == 1
    end

    def administrator?
      @controller.authenticate_administrator!
    end

    def user?
      @controller.authenticate_user!
    end
  end
end

privacy_filter_spec.rb

require "app/models/privacy_filter"

describe PrivacyFilter do

  let (:controller) { mock("controller", :authenticate_administrator! => nil, :authenticate_user! => nil, :params => {}) }

  it "allows access to the root article" do
    controller.stub!(:params => {:id => 1})

    PrivacyFilter.filter(controller).should be_true
  end

  it "allows access for administrators" do
    controller.stub!(:authenticate_administrator! => true)

    PrivacyFilter.filter(controller).should be_true
  end

  it "allows access to users" do
    controller.stub!(:authenticate_user! => true)

    PrivacyFilter.filter(controller).should be_true
  end
end