Extra arguments for Factory Girl

Question

I need to pass extra arguments to factory girl to be used in a callback. Something like this (but more complex really):

Factory.define :blog do |blog|
  blog.name "Blah"

  blog.after_create do |blog|
    blog.posts += sample_posts
    blog.save!
  end
end

and then create it with something like this:

Factory.create(:blog, :sample_posts => [post1, post2])

Any ideas how to do it?

Answer 1

One option would be to create a virtual accessor for extra posts that the after_create hook checks:

class Blog
  has_many :posts
  attr_accessible :name, :title, ... # DB columns
  attr_accessor   :sample_posts      # virtual column
end

Factory.define :blog do |blog|
  blog.name 'Blah'

  blog.after_create do |b|
    b.posts += b.sample_posts
    b.save!
  end
end

Factory(:blog, :sample_posts => [post1, post2])

Answer 2

Another option would be to use build instead of create and add :autosave to the collection:

class Blog
  has_many :posts, :autosave => true
end

Factory.define :blog do |blog|
  blog.name 'Blah'
  blog.posts { |_| [Factory.build(:post)] }
end

Factory(:blog, :posts => [post1, post2])
#or
Factory.build(:blog, :posts => [unsavedPost1, unsavedPost2])

Answer 3

Apparently, this is not possible at the moment without workarounds that require modifying the model itself. This bug is reported in: http://github.com/thoughtbot/factory_girl/issues#issue/49