To use a custom firefox profile for Selenium-webdriver in ruby

monkey_patch_firefox_profile.rb

module Selenium
  module WebDriver
    module Firefox
      class Profile
        def layout_on_disk
          firefox_profile = File.expand_path(File.join(File.dirname(__FILE__),'firefox_profile'))
          profile_dir = create_tmp_copy(firefox_profile)
          FileReaper << profile_dir

          install_extensions(profile_dir)
          delete_lock_files(profile_dir)
          delete_extensions_cache(profile_dir)
          update_user_prefs_in(profile_dir)

          puts "Using temporary Firefox profile in: #{profile_dir} from #{firefox_profile}"
          profile_dir
        end
      end
    end # Firefox
  end # WebDriver
end # Selenium