## test_unit.rb

    test "should create a comment" do
      user = Factory.create_user
      ballot = Factory.create_with_requirements(:ballot)

      assert user.comments_count == 0
      assert ballot.comments_count == 0


      first_post = Comment.create(
        :body => "this is a test",
        :user => user,
        :ballot => ballot)
      assert first_post.save

      user.reload
      ballot.reload

      assert user.comments_count == 1
      assert ballot.comments_count == 1

## factory.rb
module Factory
  def self.create_user(attributes = {})
    default_attributes = {
      :login => rand_str,
      :email  => "#{rand_str}@test.com",
      :password => "test",
      :password_confirmation => "test"
    }
    user = User.new(default_attributes.merge(attributes))
    user.save
    user
  end