Ruby Roulette wheel that places a bet on 13.

Lucky 13 Payout

require 'rubygems'
require 'open-uri'
require 'json'

class Lucky13Payout
  def initialize(location={:playing_in_usa=>true})
    @slots_on_board= location[:playing_in_usa] ? 38 : 37
  end
  
  def bet_and_spin_wheel(wager)
    spin_wheel == 13 ? wager * @slots_on_board : 0
  end
  
  def spin_wheel
    JSON.parse(open('http://roulette.engineyard.com/')).read['winning_number'].to_i rescue 0
  end
end

unless $test_run
  puts 'Place your bet'
  puts Lucky13Payout.new.bet_and_spin_wheel(gets.chomp.to_i)
end

Test for roulette wheel

require 'test/unit'
require 'rubygems'
require 'shoulda'
require 'mocha'
$test_run= true
require File.join(File.dirname(__FILE__), 'lucky_13.rb')

class Lucky13PayoutTest < Test::Unit::TestCase
  context 'Rolling and calculating winnings' do
    setup do
      @payout= Lucky13Payout.new
      @wager= 5
    end

    should 'not have any payout if 13 isn\'t landed on' do
      @payout.stubs(:spin_wheel).returns(21)
      assert_equal @payout.bet_and_spin_wheel(@wager), 0
    end
    
    should 'spin the wheel and return the winning number' do
      assert_instance_of Fixnum, @payout.spin_wheel
    end

    context 'Winning spins on' do
      context 'USA board' do
        setup{ @payout.expects(:spin_wheel).returns(13) }
        should 'payout 38 to 1 if we land on 13' do
          payout= 190
          assert_equal @payout.bet_and_spin_wheel(@wager), payout
        end
      end
    
      context 'European or French board' do
        setup do
          @payout= Lucky13Payout.new(:playing_in_usa=>false)
          @payout.expects(:spin_wheel).returns(13) 
        end
        should 'payout 37 to 1 if we land on 13' do
          payout=185
          assert_equal @payout.bet_and_spin_wheel(@wager), payout        
        end
      end
    end
  end
end