Getting Started: Capybara + Selenium + Custom user-agent, chrome settings

capybara_custom_chrome_headless.rb

require 'capybara'
require 'selenium/webdriver'
require 'capybara/dsl'
include Capybara::DSL

Capybara.run_server = false

# setting driver
# rack_test is default and non js
# selenium_chome_headless seems best headless option
# poltergist has page.driver.network_traffic ability

Capybara.register_driver(:iphone_headless) do |app|
  user_agent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A334 Safari/7534.48.3'
  capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: { args: (%w[ headless disable-gpu hide-scrollbars ] << "--user-agent='#{user_agent}'") }
  )
  Capybara::Selenium::Driver.new(app, browser: :chrome, desired_capabilities: capabilities)
end

Capybara.default_driver = :iphone_headless
#Capybara.default_driver = :selenium_chrome_headless
#Capybara.default_driver = :selenium_chrome

# change window size
# desktop 992x600, mobile 375x667
page.driver.browser.manage.window.resize_to(375, 667)

visit 'https://www.google.com'
page.save_screenshot('screenshot.png')