A spec for the base58.rb code at http://carsonified.com/blog/dev/conversational-and-short-urls-on-rails/

base58_spec.rb

require 'spec_helper'

describe Base58 do
  it "should handle creating encoded strings over 2 characters long" do
    (1..100000).each do |i|
      i.should encode_and_decode_to(i)
    end
  end
end

class EncodeDecodeCorrectly
  def initialize(i)
    @encoded = Base58.encode(i)
  end
  def matches?(target)
    @target = target
    # puts @encoded
    return Base58.decode(@encoded) == target
  end
  def failure_message
    "expected #{@target} to encode and decode correctly: encoded is #{@encoded}"
  end
  def negative_failure_message
    "expected #{@target} to not encode and decode correctly: encoded is #{@encoded}"
  end
end
def encode_and_decode_to(i)
  EncodeDecodeCorrectly.new(i)
end