game_spec.rb

$:.unshift(File.dirname(__FILE__))
require 'spec_helper'

module BowlongGameMacro
  class BowlongGamePlayer
    def initialize
      @game = Game.new
    end

    def roll_spare
      @game.roll(5)
      @game.roll(5)
    end

    def roll_strike
      @game.roll(10)
    end

    def roll_gutter
      @game.roll(0)
    end

    def roll_on_frame(*pins)
      pins.each do |pin|
        @game.roll(pin)
      end
    end
    alias :roll :roll_on_frame

    def score
      @game.score
    end
  end

  def self.included(base)
    base.extend(ClassMethods)
    base.instance_eval do
      alias :score :it
    end
  end

  module ClassMethods
    def play_game(desc = nil, &block)
      before do
        @__player = BowlongGamePlayer.new
        @__player.instance_eval(&block)
      end
      subject { @__player.score }
    end
  end
end

describe Game, "#score" do
  include BowlongGameMacro

  context "すべてガターの場合" do
    play_game { 20.times { roll_gutter } }
    score { should == 0 }
  end

  context "すべて1ピンの場合" do
    play_game { 20.times { roll_on_frame(1) } }
    score { should == 20 }
  end

  context "スペアの場合" do
    play_game do
      roll_spare
      roll_on_frame(4, 3)
      16.times { roll_gutter }
      # (10 + 4) + 4 + 3 => 21
    end
    describe "スペアの次の投球で倒したピンがボーナス加算される" do
      score { should == 21 }
    end
  end

  context "ストライクの場合" do
    play_game do
      roll_strike
      roll_on_frame(4, 3)
      16.times { roll_gutter }
      # 10 + (4 + 3) + 4 + 3 => 24
    end
    describe "次のフレームの得点がボーナス加算される" do
     score { should == 24 }
    end
  end

  context "ストライク、ガター、スペアの場合" do
    play_game do
      roll_strike
      roll_on_frame(0, 10)
      roll_on_frame(7, 2)
      (7 * 2).times { roll_gutter }
      # 10 + (0 + 10) + 10 + (7) + 7 + 2 => 46
    end
    describe "ストライク後のフレームが加算されて、かつスペアの加算も成立する" do
      score { should == 46 }
    end
  end

  context "紆余曲折あったゲームの場合" do
    play_game do
      [1,4,4,5,6,4,5,5,10,0,1,7,3,6,4,10,2,8,6].each do |pin|
        roll(pin)
      end
    end
    describe "Bob Martinの受け入れケースのスコア通りになる" do
      score { should == 133 }
    end
  end
end