bowling.py

import unittest

class Game:

    rolls = [0] * 21
    current_roll = 0

    def roll(self,pins):
        self.rolls[self.current_roll] = pins
        self.current_roll += 1

    def score(self):
        sc = 0
        frameindex = 0
        for frame in xrange(0,10):
            if self.is_strike(frameindex): 
                sc += 10 + self.strike_bonus(frameindex) 
                frameindex +=1
            elif self.is_spare(frameindex):
                sc += 10 + self.spare_bonus(frameindex)
                frameindex += 2
            else:
                sc += self.sum_of_balls(frameindex)
                frameindex += 2

        return sc
  
    def is_strike(self,frameindex):
        return self.rolls[frameindex] == 10

    def strike_bonus(self,frameindex):
        return self.rolls[frameindex+1] + self.rolls[frameindex+2]+ self.rolls[frameindex+2]

    def spare_bonus(self,frameindex):
         return self.rolls[frameindex+2]

    def sum_of_balls(self,frameindex):
        return self.rolls[frameindex] + self.rolls[frameindex+1]

    def is_spare(self,frameindex):
        return self.sum_of_balls(frameindex) == 10

class TestBowling(unittest.TestCase):

    def setUp(self):
        self.g = Game()

    def rollMany(self,n,pins):
        for i in xrange(0,n):
            self.g.roll(pins)            

    def rollSpare(self):
        self.g.roll(5)
        self.g.roll(5)

    def rollStrike(self):
        self.g.roll(10)

    def test_perfect_game(self):
        self.rollMany(12,10)
        self.assertEquals(300, self.g.score())

    def test_gutter_game(self):
        self.rollMany(20,0)
        self.assertEquals(0, self.g.score())
    
    def test_all_ones(self):
        self.rollMany(20,1)
        self.assertEquals(20, self.g.score())
    
    def test_one_spare(self):
        self.rollSpare()
        self.g.roll(3)
        self.rollMany(17,0)
        self.assertEquals(16,self.g.score())

    def test_one_strike(self):
        self.rollStrike()
        self.g.roll(3)
        self.g.roll(4)
        self.rollMany(16,0)
        self.assertEquals(24,self.g.score())

if __name__ == "__main__":
    unittest.main()