Kata: The Bowling Game

bowling.py

import pytest

class Game:
    def __init__(self):
        self.frames = [[]]
        self.allow_bonus_roll = False

    @property
    def last_frame(self):
        return self.frames[-1]

    @property
    def total_frames(self):
        return len(self.frames)

    def validate_roll(self, pins):
        if pins < 0:
            raise ValueError('Cannot roll less than zero pins.')

        if pins > 10:
            raise ValueError('Cannot roll more than ten pins.')

        if sum(self.last_frame) > 10:
            raise ValueError('You can only clear 10 pins in a single frame.')

        if self.total_frames > 10 and sum(self.frames[9]) < 10:
            raise ValueError('Cannot bowl more than 10 frames.')

    def roll(self, pins):
        self.last_frame.append(pins)
        self.validate_roll(pins)

        if len(self.last_frame) == 2 or pins == 10:
            self.frames.append([])

    def frame_is_a_strike(self, frame):
        return frame == [10]

    def score_for_frame_with_bonuses(self, i):
        total = sum(self.frames[i])

        try:
            if self.frame_is_a_strike(self.frames[i]):
                total += self.frames[i + 1][0]

                if len(self.frames[i + 1]) == 2:
                    total += self.frames[i + 1][1]
                else:
                    total += self.frames[i + 2][0]

            elif total == 10:
                total += self.frames[i + 1][0]
        except IndexError:
            pass

        return total

    def score(self):
        total = 0

        for i in xrange(self.total_frames):
            total += self.score_for_frame_with_bonuses(i)

        return total

def test_the_score_starts_at_zero():
    game = Game()
    assert game.score() == 0

def test_rolling_less_than_zero_is_not_allowed():
    game = Game()
    with pytest.raises(ValueError) as e:
        game.roll(-1)
    assert e.value.message == 'Cannot roll less than zero pins.'

def test_rolling_zero_is_allowed():
    game = Game()
    game.roll(0)
    assert game.score() == 0

def test_rolling_greater_than_ten_is_not_allowed():
    game = Game()
    with pytest.raises(ValueError) as e:
        game.roll(11)
    assert e.value.message == 'Cannot roll more than ten pins.'

def test_a_single_roll():
    game = Game()
    game.roll(5)
    assert game.score() == 5

def test_two_rolls_without_spare():
    game = Game()
    game.roll(5)
    game.roll(3)
    assert game.score() == 8

def test_more_than_ten_pins_in_a_frame():
    game = Game()
    game.roll(5)
    with pytest.raises(ValueError) as e:
        game.roll(6)
    assert e.value.message == 'You can only clear 10 pins in a single frame.'

def test_three_rolls():
    game = Game()
    game.roll(5)
    game.roll(3)
    game.roll(7)
    assert game.score() == 15

def test_spare_includes_bonus_roll():
    game = Game()
    game.roll(5)
    game.roll(5)
    game.roll(7)
    assert game.score() == 24

def test_spare_may_have_no_bonus():
    game = Game()
    game.roll(5)
    game.roll(5)
    game.roll(0)
    assert game.score() == 10

def test_strike_includes_first_bonus_roll():
    game = Game()
    game.roll(10)
    game.roll(7)
    assert game.score() == 24

def test_spare_missing_next_roll():
    game = Game()
    game.roll(5)
    game.roll(5)
    assert game.score() == 10

def test_strike_includes_second_bonus_roll():
    game = Game()
    game.roll(10)
    game.roll(7)
    game.roll(2)
    assert game.score() == 28

def test_strike_could_be_followed_by_another_strike():
    game = Game()
    game.roll(10)
    game.roll(10)
    game.roll(2)
    assert game.score() == 36

def test_too_many_rolls():
    game = Game()
    for roll in xrange(20):
        game.roll(3)

    with pytest.raises(ValueError) as e:
        game.roll(5)
    assert e.value.message == 'Cannot bowl more than 10 frames.'

def test_last_frame_spare_allows_bonus_roll():
    game = Game()
    for i in xrange(18):
        game.roll(1)
    game.roll(8)
    game.roll(2)
    game.roll(3)

    assert game.score() == 34

def test_perfect_game():
    game = Game()
    for i in xrange(11):
        game.roll(10)

    assert game.score() == 300

How do I run this game

@AKinbusola you should be able to run this with pytest:

pytest bowling.py

If pytest it's not installed:

pip install pytest