Pair Programming Session w/ @marksim

bowling.rb

class Bowling

  def initialize
    @rolls = []
  end

  def roll(pins)
    @rolls << pins
  end

  def score
    index = 0
    (0..9).map do |frame|
      if @rolls[index] == 10
        frame_score = 10 + @rolls[index+1] + @rolls[index+2]
        index += 1
      else
        frame_score = @rolls[index] + @rolls[index+1]
        frame_score += @rolls[index+2] if frame_score == 10
        index += 2
      end 
      frame_score
    end.inject {|a, m| a + m}
  end
end

bowling_spec.rb

require 'spec_helper'

describe Bowling do
  let(:game) { Bowling.new }
  it "adds each roll to the score when less than 10" do
    20.times do 
      game.roll(4)
    end
    game.score.should == 80
  end
  it "adds a spare when two rolls add up to 10" do
    2.times do 
      game.roll(4)
    end
    game.roll(2)
    game.roll(8)
    16.times do 
      game.roll(4)
    end
    game.score.should == 86
  end

  it "adds the next two when a strike is thrown" do
    game.roll(10)
    18.times do
      game.roll(4)
    end
    game.score.should == 90
  end

  it "should add another strike in the last frame" do
    18.times do 
      game.roll(4)
    end
    game.roll(10)
    game.roll(10)
    game.roll(2)
    game.score.should == 94
  end

  it "should give 300 for a perfect game" do
    12.times do
      game.roll(10)
    end
    game.score.should == 300
  end
end