gistfile1.rb

  config.after(:suite) do
    sessions = Capybara.send(:session_pool).values
    pids = sessions.map do |session|
      if Capybara::Webkit::Driver === session.driver
        session.driver.browser.instance_variable_get(:@connection).pid
      end
    end
    Process.kill("KILL", *pids.compact)
  end