Confirming access to alerts in a StackOverflow question, take 2

gistfile1.rb

#!/bin/env ruby
# encoding: utf-8

# Trying to replicate error described in a StackOverflow Question
# http://stackoverflow.com/questions/31065711/watir-webdriver-does-not-show-dialogs-in-firefox-when-finished-testing

require 'os'
require 'headless'
require 'watir-webdriver'
require 'yaml'

class MyBrowser
  attr_accessor :b, :h

  def initialize
    setup
  end

  def confirm_alert_appears
    @b.goto "http://www.w3schools.com/js/tryit.asp?filename=tryjs_alert"

    frame_container = @b.div(:class => "container").div(:class => "iframecontainer")
    iframe = frame_container.div(:class => "iframewrapper").iframe(:id => "iframeResult")
    iframe.button(:onclick => "myFunction()").click

    result = true if @b.alert.exists?

    @b.alert.close if @b.alert.exists?

    raise 'Could not access alerts' unless result
  end

  private

  def setup
    if !@b
      decapitate if OS.linux?
      @b = Watir::Browser.new :firefox
    end
  end

  def decapitate
    if !@h
      @h = Headless.new
      @h.start
    end
  end

end

begin
  m = MyBrowser.new

  m.confirm_alert_appears

  # Save the MyBrowser object to file
  File.open('some_file.txt', 'w') {|f| f.write(YAML.dump(m)) }

  # ...
  # Do whatever you want to do,
  # wait however long you want to wait.
  m = nil
  # ...

  sleep(5)

  m = YAML.load(File.read('some_file.txt'))

  m.confirm_alert_appears
ensure
  m.b.close if m.b
  m.h.destroy_sync if m.h
end