class ActionDispatch::SystemTestCase

def url_helpers
  @url_helpers ||=
    if ActionDispatch.test_app
      Class.new do
        include ActionDispatch.test_app.routes.url_helpers
        include ActionDispatch.test_app.routes.mounted_helpers
        def url_options
          default_url_options.reverse_merge(host: app_host)
        end
        def app_host
          Capybara.app_host || Capybara.current_session.server_url || DEFAULT_HOST
        end
      end.new
    end
end