game.rb

class Game
  def initialize()
    @score = 0
    @frame = []
    @frame_number = 0
    @first = true
  end
  def roll(number_of_pins)
    if @first
      @frame.push(number_of_pins)
#      @frame.last += number_of_pins if @frame.last == 10
      @first = false
    else
      @frame[@frame_number] += number_of_pins
      @first = true
      @frame_number += 1
    end
  end
  def score()
    @frame.each do |n|
      @score += n
    end
    @score
  end
  def frame
    @frame_number
  end
end

test.rb

require './game'
describe Game do
  it "should add increment your score" do
  g = Game.new
  g.roll(10)
  g.score.should eq(10)
  end

  it "should accept two rolls per frame"  do
    g = Game.new
    g.roll(5)
    g.roll(2)
    g.frame.should eq(1)
  end

#  it "should calculate a spare" do
#    g = Game.new
#    g.roll(5)
#    g.roll(5)
#    g.roll(2)
#    g.roll(0)
#    g.score.should eq(14)
#  end
end