Question

设计

我有一个通过多态关联属于个人资料的用户模型。我选择此设计的原因可以找到here。总而言之，该应用程序的许多用户具有完全不同的配置文件。

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

选择这个设计后，我很难做出好的测试。使用FactoryGirl和RSpec，我不确定如何以最有效的方式声明关联。

首次尝试

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

评论/其他想法

正如用户规范中的评论所述，使用Artist似乎很脆弱。如果我的工厂将来改变怎么办？

也许我应该使用factory_girl callbacks并定义“艺术家用户”和“音乐家用户”？所有的意见都表示赞赏。

Answer 1

虽然有一个公认的答案，但这里有一些使用新语法的代码对我有用，可能对其他人有用。

<强>规格/ factories.rb

FactoryGirl.define do

  factory :musical_user, class: "User" do
    association :profile, factory: :musician
    #attributes for user
  end

  factory :artist_user, class: "User" do
    association :profile, factory: :artist
    #attributes for user
  end

  factory :artist do
    #attributes for artist
  end

  factory :musician do
    #attributes for musician
  end
end

<强>规格/模型/ artist_spec.rb

before(:each) do
  @artist = FactoryGirl.create(:artist_user)
end

这将创建艺术家实例以及用户实例。所以你可以打电话：

@artist.profile

获取Artist实例。

Answer 2

使用这样的特征;

FactoryGirl.define do
    factory :user do
        # attributes_for user
        trait :artist do
            association :profile, factory: :artist
        end
        trait :musician do
            association :profile, factory: :musician
        end
    end
end

现在您可以通过FactoryGirl.create(:user, :artist)

获取用户实例

Answer 3

Factory_Girl回调会让生活变得更轻松。这样的事情怎么样？

Factory.define :user do |user|
  #attributes for user
end

Factory.define :artist do |artist|
  #attributes for artist
  artist.after_create {|a| Factory(:user, :profile => a)}
end

Factory.define :musician do |musician|
  #attributes for musician
  musician.after_create {|m| Factory(:user, :profile => m)}
end

Answer 4

您也可以使用嵌套工厂（继承）解决此问题，这样您就可以为每个类创建基本工厂嵌套从这个基本父级继承的工厂。

FactoryGirl.define do
    factory :user do
        # attributes_for user
        factory :artist_profile do
            association :profile, factory: :artist
        end
        factory :musician_profile do
            association :profile, factory: :musician
        end
    end
end

您现在可以访问嵌套工厂，如下所示：

artist_profile = create(:artist_profile)
musician_profile = create(:musician_profile)

希望这有助于某人。

Answer 5

工厂中的多态关联似乎与常规Rails关联的行为相同。

如果你不关心模特的属性，那么还有另一种不那么冗长的方式。＃34; belongs_to＆＃34;关联方（本例中的用户）：

# Factories
FactoryGirl.define do
  sequence(:email) { Faker::Internet.email }

  factory :user do
    # you can predefine some user attributes with sequence
    email { generate :email }
  end

  factory :artist do
    # define association according to documentation
    user 
  end
end

# Using in specs    
describe Artist do      
  it 'created from factory' do
    # its more naturally to starts from "main" Artist model
    artist = FactoryGirl.create :artist        
    artist.user.should be_an(User)
  end
end

FactoryGirl协会：https://github.com/thoughtbot/factory_girl/blob/master/GETTING_STARTED.md#associations

Answer 6

我目前使用此实现来处理FactoryGirl中的多态关联：

在/spec/factories/users.rb中：

FactoryGirl.define do

  factory :user do
    # attributes for user
  end

  # define your Artist factory elsewhere
  factory :artist_user, parent: :user do
    profile { create(:artist) }
    profile_type 'Artist'
    # optionally add attributes specific to Artists
  end

  # define your Musician factory elsewhere
  factory :musician_user, parent: :user do
    profile { create(:musician) }
    profile_type 'Musician'
    # optionally add attributes specific to Musicians
  end

end

然后，照常创建记录：FactoryGirl.create(:artist_user)

FactoryGirl和多态关联

设计

首次尝试

评论/其他想法

6 个答案: