fancy-pants.rb

module NavigationHelpers
  def path_to(page_name)
    case page_name

    #services
    when /the list of services/
      services_path
    when /a new service/
      new_service_path
    when /edit the service named "([^"]*)"/
      edit_service_path(fetch_service(name: $1))
    
    #subscriptions
    when /a new subscription for user "([^"]*)"/
      new_user_subscription_path(fetch_user(username: $1))  
    end

  end
end

World(NavigationHelpers)

module FetchHelpers
  FETCH_REGEX = /^fetch_(.+)/

  def method_missing(method, *args)
    if method.to_s =~ FETCH_REGEX
      fetch $1, *args
    else
      super
    end
  end

  private
  def fetch(klass, options)
    klass.constantize.where(options).first or
      raise "No #{klass} found for #{options.inspect}"
  end
end

World(FetchHelpers)