wait_for_ajax helper for capyabara

capyabara_helper_methods.rb

module CapybaraHelperMethods
  def wait_for_ajax
    counter = 0
    while !finished_all_ajax_requests?
      counter += 1
      sleep 0.2
      raise "AJAX request took too long." if counter >= (Capybara.default_wait_time * 5)
    end
  end

  def finished_all_ajax_requests?
    active = page.evaluate_script <<-SCRIPT.strip.gsub(/\s+/,' ')
      (function () {
        if (typeof jQuery != 'undefined') {
          return jQuery.active;
        }
        else {
          console.error("jQuery was undefined on " + document.URL + " - will retry...");
          return -1;
        }
      })()
    SCRIPT

    active && active.zero?
  end
end

RSpec.configuration.include CapybaraHelperMethods, :type => :feature

based on https://coderwall.com/p/aklybw/wait-for-ajax-with-capybara-2-0