factory_girl + Rails 3.2.1 / legacy fanctional test

factories.rb

class FactoryGirl::TestHelper
  include ActionDispatch::TestProcess

  def self.fixture_file_upload(*args)
    self.new.fixture_file_upload(*args)
  end

  def self.fixture_path
    File.join(File.dirname(__FILE__) + '/fixtures/')
  end
end

Factory.define :file do |f|
  f.asset { FactoryGirl::TestHelper.fixture_file_upload('/files/logo.png', 'image/png', true) }
end