Bowling TDD Kata

bowling.py

STRIKE = 'X-'

def score_frame(frame, next_frame):
    if frame[:2] == STRIKE:
        if next_frame == STRIKE:
            return 20
        if next_frame is LAST_FRAME:
            first_ball_next_frame = int(frame[2])
            second_ball_next_frame = int(frame[3])
        else:
            first_ball_next_frame = int(next_frame[0])
            second_ball_next_frame = int(next_frame[1])
        return 10 + first_ball_next_frame + second_ball_next_frame

    first_ball = int(frame[0])
    second_ball = int(frame[1])
    if first_ball + second_ball == 10:
        if next_frame is LAST_FRAME:
            third_ball = int(frame[2])
            return 10 + third_ball
        return 10 + int(next_frame[0])
    return first_ball + second_ball


LAST_FRAME = object()


def score(game):
    frames = game.split()
    next_frames = frames[1:] + [LAST_FRAME]
    result = 0
    for frame, next_frame in zip(frames, next_frames):
        result += score_frame(frame, next_frame)
    return result

test_bowling.py

from bowling import score

def test_all_zeroes():
    assert score('00 00 00 00 00 00 00 00 00 00') == 0

def test_one_point():
    assert score('01 00 00 00 00 00 00 00 00 00') == 1
    assert score('00 00 00 00 00 00 00 00 00 01') == 1

def test_more_than_one_point():
    assert score('04 00 00 00 00 00 00 00 00 00') == 4
    assert score('40 00 00 00 00 00 00 00 00 00') == 4

def test_scoring_in_muliple_frames():
    assert score('04 06 07 00 00 00 00 00 00 00') == 17

def test_scoring_multiple_in_one_frame():
    assert score('26 00 00 00 00 00 00 00 00 00') == 8

def test_spare_followed_by_zero():
    assert score('28 00 00 00 00 00 00 00 00 00') == 10

def test_spare_followed_by_nonzero():
    # the score for a spare = 10 plus your first ball in the next frame
    # and the next frame is scored separately
    assert score('28 30 00 00 00 00 00 00 00 00') == 10 + 3 + 3

def test_two_spares():
    assert score('28 37 40 00 00 00 00 00 00 00') == (10 + 3) + (10 +4) + 4

def test_strike_followed_by_zero():
    assert score('X- 00 00 00 00 00 00 00 00 00') == 10

def test_strike_followed_by_nonzero():
    assert score('X- 40 00 00 00 00 00 00 00 00') == (10 + 4) + (4 + 0)

def test_strike_followed_by_two_nonzero_balls():
    assert score('X- 43 00 00 00 00 00 00 00 00') == (10 + 4 + 3) + (4 + 3)

def test_two_strikes_in_a_row():
    assert score('X- X- 30 00 00 00 00 00 00 00') == (10 + 10) + (10 + 3) + 3

def test_three_strikes_in_a_row():
    assert score('X- X- X- 60 00 00 00 00 00 00') == 20 + 20 + (10 + 6) + 6


def test_last_frame_is_spare():
    assert score('00 00 00 00 00 00 00 00 00 376') == (10 + 6)

def test_last_frame_is_strike_with_zero():
    assert score('00 00 00 00 00 00 00 00 00 X-00') == 10 + 0 + 0

def test_last_frame_is_strike_with_one_nonzero():
    assert score('00 00 00 00 00 00 00 00 00 X-10') == 10 + 1 + 0

def test_last_frame_is_strike_with_two_nonzero():
    assert score('00 00 00 00 00 00 00 00 00 X-18') == 10 + 1 + 8