Game of Life

game.py

class Game(object):
    def __init__(self, initial_state: set):
        self.state = initial_state

    @staticmethod
    def get_neighbours(x: int, y: int) -> set:
        offsets = [(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)]

        return set([(x + i, y + j) for (i, j) in offsets])

    def get_live_neighbours(self, x: int, y: int) -> set:
        return {cell for cell in self.get_neighbours(x, y) if cell in self.state}

    def generate_all_candidates(self) -> set:
        candidates = set()
        for x, y in self.state:
            candidates.add((x, y))

            for neighbour in self.get_neighbours(x, y):
                candidates.add(neighbour)

        return candidates

    def next_state(self) -> set:
        new_state = set()

        for x, y in self.generate_all_candidates():

            live_neighbours_count = len(self.get_live_neighbours(x, y))

            if (x, y) in self.state:
                if 1 < live_neighbours_count < 4:
                    new_state.add((x, y))
            else:
                if live_neighbours_count == 3:
                    new_state.add((x, y))

        return new_state

test_game.py

from game import Game


def test_initial_state():
    state = [(0, 0), (1, 1)]
    g = Game(state)
    assert g.state == state


def test_get_neighbours():
    assert Game.get_neighbours(0, 0) == {
        (-1, -1),
        (-1, 0),
        (-1, 1),
        (0, -1),
        (0, 1),
        (1, -1),
        (1, 0),
        (1, 1),
    }
    assert Game.get_neighbours(1, 1) == {
        (0, 0),
        (0, 1),
        (0, 2),
        (1, 0),
        (1, 2),
        (2, 0),
        (2, 1),
        (2, 2),
    }


def test_get_live_neighbours():
    state = [(0, 0), (1, 1)]
    g = Game(state)
    assert g.get_live_neighbours(0, 0) == {(1, 1)}
    assert g.get_live_neighbours(1, 1) == {(0, 0)}
    assert g.get_live_neighbours(0, 1) == {(0, 0), (1, 1)}
    assert g.get_live_neighbours(3, 3) == set()

    state = [(1, 1), (2, 0), (2, 2)]
    g = Game(state)
    assert g.get_live_neighbours(2, 1) == {(1, 1), (2, 0), (2, 2)}


def test_generate_all_candidates():
    state = [(0, 0), (1, 1)]
    g = Game(state)
    assert g.generate_all_candidates() == {
        (0, 0),
        (1, 1),
        (-1, -1),
        (-1, 0),
        (-1, 1),
        (0, -1),
        (0, 1),
        (1, -1),
        (1, 0),
        (1, 1),
        (0, 0),
        (0, 1),
        (0, 2),
        (1, 0),
        (1, 2),
        (2, 0),
        (2, 1),
        (2, 2),
    }


def test_next_state():
    g = Game([(12, 13)])
    assert g.next_state() == set()

    g = Game([(1, 1), (2, 0)])
    assert g.next_state() == set()

    g = Game([(1, 1), (2, 0), (0, 2)])
    assert g.next_state() == {(1, 1)}

    g = Game([(1, 1), (2, 0), (2, 2)])
    assert g.next_state() == {(1, 1), (2, 1)}