# auto_validate.rb
  require "dm-types" # not sure of that...
  if property.type.ancestors.include?(Types::Enum)
    validates_within property.name, options_with_message({:set => property.type.flag_map.values}, property, :within)
  end

# auto -validate_spec
 describe 'for Enum properties' do
    require 'dm-types' # not sure if it is ok to require dm-types here
    before :all do
      class ColorBoat
        include DataMapper::Resource
        property :id,     Integer,  :serial => true
        property :color,  Enum[:red, :yellow, :blue]
      end
    end

    before do
      @boat = ColorBoat.new
    end

    it "should accept red color" do
      @boat.color = :red
      @boat.should be_valid
    end

    it "should not accept green color" do
      @boat.color = :green
      @boat.should_not be_valid
      @boat.errors.on(:color).should_not be_empty
    end

  end