gistfile1.rb

require 'test/unit'
class Size
  include Comparable
  attr_reader :size
  
  SIZE_LIST = %w(xxs xs s m l xl xxl)

  def self.method_missing(m,*args,&blk)
    if SIZE_LIST.include?(m.to_s)
      return new(m.to_s)
    else
      super
    end
  end
  
  def initialize(s)
    @size = s.downcase
  end
  
  def <=>(another)
    return SIZE_LIST.index(size) <=> SIZE_LIST.index(another.size)
  end
end

class SizeTest < Test::Unit::TestCase
  def test_comparable
    xl = Size.new('XL')
    l = Size.new('L')
    m = Size.new('M')
    assert xl > l
    assert l > m
    assert xl > m
    m2 = Size.new('m')
    assert m2 == m
  end

  def test_magic_methods
    xl = Size.xxl
    l = Size.xl
    assert xl > l
  end
end