FactoryGirl with polymorphic associations

factories.rb

FactoryGirl.define do
  factory :slideshow_image, class: "Image" do
    association :imageable, :factory => :slideshow
    # other attributes for slideshow model
  end
  
  factory :article_image, class: "Image" do
    association :imageable, :factory => :article
    # other attributes for article model
  end
end

models.rb

class Image < ActiveRecord::Base
  mount_uploader :photo, ImageUploader
  belongs_to :imageable, :polymorphic => true

end

class Slideshow < ActiveRecord::Base
  has_many :images, :as => :imageable, :dependent => :destroy

end

class Article < ActiveRecord::Base
  has_many :images, :as => :imageable, :dependent => :destroy

end

specs.rb

before(:each) do
  @article_image = FactoryGirl.create(:article_image)
  @article = @article_image.article
end