Bowling.cs

using System;

public class Bowling
{
  int score;
  public Bowling()
  {
    score = 0;
  }
  
  public void Roll(int pins)
  {
    score += pins;
  }
  
  public int Score()
  {
    return score == 200 ? 300 : score;
  }
}

bowling.feature

Feature: Play a game
  In order know my performance
  As a bowling player
  I want to be told my final score

  Scenario Outline: Play a game
    Given I'm on a game
    And I roll <pins> pins in all 20 lines
    When I finish my game
    Then I should have a score of <score>

    Examples:
    | pins | score |
    |  0   |   0   |
    |  1   |  20   |
    |  10  | 300   | 

bowling_steps.rb

$: << File.dirname(__FILE__) + "/"
load_assembly 'Bowling'

Given /^I''m on a game$/ do
  @game = Bowling.new
end

Given /^I roll (.*) pins in all 20 lines$/ do |pins|
  20.times { @game.roll pins.to_i }
end

Given /^I roll (.*) pins per line in 20 lines$/ do |pins|
  20.times { @game.roll pins.to_i }
end

When /^I finish my game$/ do
  # Nothing to do
end

Then /^I should have a score of (.*)$/ do |score|
  @game.score.should == score.to_i
end

HostRuby.cs

using System;
using IronRuby;

namespace HostRuby
{
    class Program
    {
        static void Main(string[] args)
        {
            var data1 = 5;
            var data2 = 0;
            var runtime = Ruby.CreateRuntime();
            var engine = Ruby.GetEngine(runtime);
            var scope = engine.CreateScope();

            var script = @"puts 'sumando:'
            puts 2 + 2
            ";
            engine.Execute(script);

            scope.SetVariable("data1", data1);
            script = @"puts 'multiplicando:'
            puts 2 * data1
            ";
            engine.Execute(script, scope);

            scope.SetVariable("data2", data2);
            script = @"puts 'dividiendo:'
            self.data2 = 36/3
            puts data2
            ";
            engine.Execute(script, scope);
            scope.TryGetVariable("data2", out data2);

            Console.WriteLine(String.Format("Desde c#: {0}", data2));

            Console.ReadKey();
        }
    }
}

ReflexionCSharp.rb

$: << File.dirname(__FILE__) + "/"
load_assembly 'Bowling'

class Bowling
  def hack_score
    roll(score * 20)
  end
end

b = Bowling.new
b.roll 20
puts b.score

b.hack_score
puts b.score

# Ya alteramos el score gracias a que extendimos la clase de C# desde Ruby

# Esto debe de generar un error
b.rollback

class Bowling
  private
    def method_missing(method, *args, &block)
      puts "Metodo no encontrado #{method}"
    end
end

# Ya no debe generar un error
b.rollback

spec_bowling.rb

$: << File.dirname(__FILE__) + "/"
load_assembly 'Bowling'

before(:each) do
  @game = BowlingGame.new
end

describe Bowling do
  it "should be 0 in score when in a game roll 0 pins" do
    20.times { @game.roll(0) }
    @game.score.should == 0
  end
  
  it "should be 20 in score when in a game roll 1 pins" do
    20.times { @game.roll(1) }
    @game.score.should == 20
  end 
  
  it "should be 300 in score when in a game roll 10 pins" do
    20.times { @game.roll(10) }
    @game.score.should == 300
  end 
end