TDD demo: tests

from bowling import Game

class GameFixture:
    def __init__(self):
        self.game = Game()
        self.num_rolls = 0

    def roll(self, pins):
        self.num_rolls = self.num_rolls + 1
        self.game.roll(pins)

    def score(self):
        return self.game.score()

    def finish_game_with_zeroes(self):
        rolls_left = 20 - self.num_rolls
        for i in range(rolls_left):
            self.game.roll(0)

    def is_in_error_state(self):
        return self.game.score() == self.game.error


def test_zero_game():
    game = GameFixture()
    game.finish_game_with_zeroes()
    assert game.score() == 0


def test_all_ones():
    game = Game()
    for i in range(20):
        game.roll(1)
    assert game.score() == 20


def test_one():
    game = GameFixture()
    game.roll(1)
    game.finish_game_with_zeroes()
    assert game.score() == 1


def test_too_many_pins():
    game = GameFixture()
    for i in range(20):
        game.roll(50)
    assert game.is_in_error_state()

    # Error state persists after bad roll
    game = GameFixture()
    game.roll(11)
    game.finish_game_with_zeroes()
    assert game.is_in_error_state()

    # Error state persists even when subsequent rolls are good
    game = GameFixture()
    game.roll(11)
    game.roll(1)
    game.finish_game_with_zeroes()
    assert game.is_in_error_state()


def test_too_few_rolls():
    game = GameFixture()

    # When one roll is made
    game.roll(0)

    # Then the game can't be scored
    assert game.is_in_error_state()

    # And when a second roll is made
    game.roll(0)

    # Then the game still can't be scored
    assert game.is_in_error_state()


def test_too_many_rolls():
    # Given a game with more 21 rolls (and no expectation of a 21st roll)
    game = GameFixture()
    for i in range(21):
        game.roll(0)

    # Then the game can't be scored
    assert game.is_in_error_state()


def test_that_frame_1_doesnt_exceed_10():
    # Given a game
    game = GameFixture()

    # When the first two rolls add up to more than 10
    game.roll(7)
    game.roll(7)
    game.finish_game_with_zeroes()

    # Then the game is in an error state
    assert game.is_in_error_state()


def test_that_frame_2_doesnt_exceed_10():
    # Given a game with two rolls already made
    game = GameFixture()
    game.roll(0)
    game.roll(0)

    # When the next two rolls add up to more than 10
    game.roll(7)
    game.roll(7)
    game.finish_game_with_zeroes()

    # Then the game is in an error state
    assert game.is_in_error_state()


def test_that_frame_3_doesnt_exceed_10():
    # Given a game with four rolls already made
    game = GameFixture()
    game.roll(0)
    game.roll(0)
    game.roll(0)
    game.roll(0)

    # When the next two rolls add up to more than 10
    game.roll(7)
    game.roll(7)
    game.finish_game_with_zeroes()

    # Then the game is in an error state
    assert game.is_in_error_state()


def test_frame_2_validity_doesnt_count_frame_1():
    # Given a game with two valid frames totalling >10 pins
    game = GameFixture()
    game.roll(5)
    game.roll(5)
    game.roll(5)
    game.roll(5)

    # When the game finishes
    game.finish_game_with_zeroes()

    # Then the game is in an error state
    assert not game.is_in_error_state()


def test_frame_3_validity_doesnt_count_frame_2():
    # Given a game with three valid frames where frame 2 and 3 total >10 pins
    game = GameFixture()
    game.roll(0)
    game.roll(0)
    game.roll(5)
    game.roll(5)
    game.roll(5)
    game.roll(5)

    # When the game finishes
    game.finish_game_with_zeroes()

    # Then the game is in an error state
    assert not game.is_in_error_state()

def test_spares():
    test_next_pins = [1, 2]
    for next_pin in test_next_pins:

        # Given a game in which the first frame is a spare
        game = GameFixture()
        game.roll(6)
        game.roll(4)

        # When the next pin is n, then nothing else is scored
        game.roll(next_pin)
        game.finish_game_with_zeroes()

        # Then the final score is (10 + n + spare bonus of n)
        assert game.score() == 10 + 2 * next_pin

def test_spare_bonus_only_counts_one_extra_roll():
    # Given a game in which the first frame is a spare
    game = GameFixture()
    game.roll(6)
    game.roll(4)

    # When the next  two pins are 1s
    game.roll(1)
    game.roll(1)
    game.finish_game_with_zeroes()

    # Then only the third roll is doubled (i.e., the score is 13)
    assert game.score() == 13