auto_suggest2.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'selenium-webdriver'
  gem 'capybara'
end

require "capybara/dsl"

sess = Capybara::Session.new(:selenium_chrome)
sess.visit('https://codepen.io/moroshko/pen/LGNJMy')
sess.within_frame(:css, '#result:not([src=""])') do
  input = sess.find('#app input')
  input.click.send_keys('c')
  sess.assert_selector('li[role="option"]')
end