Rubyonrails FactoryGirl 和多态关联

设计

我有一个用户模型，它通过多态关联属于一个概要文件.我 Select 这种设计的原因可以找到here.总而言之，应用程序中有许多用户的配置文件非常不同.

class User < ActiveRecord::Base
  belongs_to :profile, :dependent => :destroy, :polymorphic => true
end

class Artist < ActiveRecord::Base
  has_one :user, :as => :profile
end

class Musician < ActiveRecord::Base
  has_one :user, :as => :profile
end

在 Select 了这种设计之后，我很难想出好的测试.使用FactoryGirl和RSpec，我不确定如何以最有效的方式声明关联.

第一次try

factories.rb

Factory.define :user do |f|
  # ... attributes on the user
  # this creates a dependency on the artist factory
  f.association :profile, :factory => :artist 
end

Factory.define :artist do |a|
  # ... attributes for the artist profile
end

user_spec.rb

it "should destroy a users profile when the user is destroyed" do
  # using the class Artist seems wrong to me, what if I change my factories?
  user = Factory(:user)
  profile = user.profile
  lambda { 
    user.destroy
  }.should change(Artist, :count).by(-1)
end

comments /其他 idea

正如用户规范中的注释所述，使用艺术家似乎很脆弱.如果我的工厂将来发生变化怎么办？

也许我应该用factory_girl callbacks来定义"艺术家用户"和"音乐家用户"？感谢所有的意见.