Test window_opened_by with FB share window

fb_share_window_test.rb

require 'capybara/dsl'
require 'selenium-webdriver'
require 'capybara'
require 'byebug'

session = Capybara::Session.new(:selenium, nil)
session.visit('https://jsfiddle.net/stichoza/EYxTJ/')
win = session.window_opened_by do
  session.within_frame('result') do
    session.click_link 'Share'
  end
end