gistfile1.rb

require "mocha"

Factory.define :post do |p|
  p.title "first post"
  p.after_build do |post|
    slug = Slug.new(:name => "first-post", :sequence => 1, :sluggable => post)
    post.stubs(:slug).returns(slug)
  end
end

class PostTest < ActiveSupport::TestCase
  # Replace this with your real tests.
  test "should have a slug" do
    post = Factory.build(:post)
    assert post.slug
    assert_equal post, post.slug.sluggable
  end
end