Capybara + Angular.js wait_for_ajax

feature_helpers.rb

require 'selenium-webdriver'

module FeatureHelpers
  DEFAULT_WAIT_TIME = 30

  Capybara.register_driver :poltergeist_debug do |app|
    Capybara::Poltergeist::Driver.new(app,
      inspector: true,
      js_errors: true,
      timeout: DEFAULT_WAIT_TIME
    )
  end

  Capybara.default_wait_time = DEFAULT_WAIT_TIME
  Capybara.javascript_driver = :poltergeist_debug

  # Public: Block until our page says there are no requests currently
  #         in progress, or we timeout.
  #
  # max_wait           - The amount of time you're willing to wait for AJAX to complete.
  # check_pause        - The amount of time between checks
  # notify_after_ticks - After this many ticks output a message about whats going on.
  #
  # Returns nothing.
  def wait_for_ajax(max_wait = Capybara.default_wait_time, check_pause = 0.1, notify_after_ticks = 10)
    ticks = 0
    new_line = false

    Timeout.timeout(max_wait) do
      until finished_all_ajax_requests?
        ticks += 1

        if (ticks % notify_after_ticks).zero?
          wait_time = (ticks * check_pause.to_f).round(1)
          debug_inplace("[waiting <time: #{wait_time}s/#{max_wait}s>] #{last_ajax_request}\r#{eol}")
          new_line = true
        end

        sleep check_pause
      end
    end

    puts if new_line # flush line
  end

  private

  def debug_inplace(message)
    $stderr.write("%s\r" % message)
    $stderr.flush  
  end

  # Private: The URL of the last active AJAX request.
  # Returns the URL if present, blank string otherwise.
  def last_ajax_request
    page.evaluate_script('window.__lastActiveRequest__').to_s
  end

  # Private: The number of AJAX requests currently in progress on the page.
  # Returns the number of active requests.
  def current_active_requests
    page.evaluate_script('window.__activeRequests__')
  end

  # Private: Check if we have no AJAX request in progress.
  # Returns false if there are active requests, true otherwise.
  def finished_all_ajax_requests?
    current_active_requests.zero?
  end
end

RSpec.configure do |config|
  config.include FeatureHelpers, type: :feature
end

request_tracking.js

(function(module) {
  'use strict';

  // Track HTTP requests so we can fix capybara specs without resorting
  // to random sleeps.
  // See: spec/support/feature_helpers.rb for how its used
  module.config(['$httpProvider',
    function($httpProvider) {
      var key = '__activeRequests__';
      var lastUrl = '__lastActiveRequest__';

      $httpProvider.interceptors.push(['$window', '$q',
        function($window, $q) {
          $window[key] = 0;

          var startRequest = function(config) {
            $window[key] += 1;
            $window[lastUrl] = config.method + ' ' + config.url;
          };

          var finishRequest = function() {
            $window[key] -= 1;

            if($window[key] < 0) {
              $window[key] = 0;
            }
          };

          return {
            request: function(config) {
              startRequest(config);
              return config;
            },

            requestError: function(rejection) {
              finishRequest();
              return $q.reject(rejection);
            },

            response: function(response) {
              finishRequest();
              return response;
            },

            responseError: function(rejection) {
              finishRequest();
              return $q.reject(rejection);
            }
          };
        }
      ]);
    }
  ]);

})(angular.module('MyModule'));