Wizard/wizard_server/game_logic/tests/test_game.py

import json
import random

import pytest

from wizard_game import (
    DECK_SIZE,
    Bid,
    GameFinished,
    GameOptions,
    IllegalActionError,
    Observation,
    Phase,
    PlayCard,
    RoundCompleted,
    TrickCompleted,
    TrickResult,
    WizardGame,
    action_from_dict,
    card_by_id,
)
from wizard_game.cards import WIZARD_ID_OFFSET


def play_random_game(num_players: int, seed: int, options: GameOptions | None = None) -> WizardGame:
    game = WizardGame(num_players, options, seed=seed)
    rng = random.Random(seed)
    rounds_completed = 0
    while not game.is_finished:
        player = game.current_player
        actions = game.legal_actions()
        assert actions, "current player must always have a legal action"
        events = game.apply(player, rng.choice(actions))
        rounds_completed += sum(isinstance(e, RoundCompleted) for e in events)
    assert rounds_completed == game.total_rounds
    return game


@pytest.mark.parametrize("num_players", [3, 4, 5, 6])
@pytest.mark.parametrize("seed", range(5))
def test_random_games_complete(num_players, seed):
    options = GameOptions(hidden_bids=seed % 2 == 0)
    game = play_random_game(num_players, seed, options)
    assert game.phase is Phase.FINISHED
    assert len(game.round_history) == game.total_rounds
    assert game.scores == list(game.round_history[-1].scores)
    for result in game.round_history:
        assert sum(result.tricks) == result.round_number
        assert sum(result.bids) != result.round_number


def test_invalid_player_count():
    with pytest.raises(ValueError):
        WizardGame(2)
    with pytest.raises(ValueError):
        WizardGame(7)


def test_deal_sizes_and_starter():
    game = WizardGame(4, seed=3, first_dealer=2)
    assert game.round_number == 1
    assert all(len(game.hand(p)) == 1 for p in range(4))
    assert game.phase is Phase.BIDDING
    assert game.current_player == 3


def test_wrong_player_rejected():
    game = WizardGame(3, seed=1, first_dealer=0)
    other = (game.current_player + 1) % 3
    with pytest.raises(IllegalActionError):
        game.apply(other, game.legal_actions()[0])


def test_illegal_bid_rejected():
    game = WizardGame(3, seed=1, first_dealer=0)
    with pytest.raises(IllegalActionError):
        game.apply(game.current_player, Bid(5))


@pytest.mark.parametrize("num_players", [3, 4, 5, 6])
def test_trump_card_is_taken_from_the_stack(num_players):
    """The trump card is dealt to nobody and every card exists only once."""
    game = WizardGame(num_players, seed=num_players)
    rng = random.Random(num_players)
    rounds_seen = 0
    while not game.is_finished:
        if game.phase is Phase.BIDDING and all(bid is None for bid in game.round.bids):
            rounds_seen += 1
            hands = [card for player in range(num_players) for card in game.hand(player)]
            assert len(hands) == len(set(hands)) == game.round_number * num_players
            trump = game.round.trump_card
            if game.round_number * num_players < DECK_SIZE:
                assert trump is not None and trump not in hands
            else:
                assert trump is None  # last round: every card was dealt
        game.apply(game.current_player, rng.choice(game.legal_actions()))
    assert rounds_seen == game.total_rounds


def find_game(predicate, num_players=4):
    for seed in range(500):
        game = WizardGame(num_players, seed=seed, first_dealer=1)
        if predicate(game.round.trump_card):
            return game
    pytest.fail("no seed produced the wanted trump card")


def test_number_trump_card_defines_trump_suit():
    game = find_game(lambda card: card is not None and card.is_number)
    assert game.round.trump_suit is game.round.trump_card.suit
    assert game.observation(0).trump_suit is game.round.trump_card.suit


def test_completed_trick_keeps_its_rounds_trump_card():
    game = WizardGame(3, seed=4)
    rng = random.Random(4)
    for _ in range(200):
        trump = game.round.trump_card
        events = game.apply(game.current_player, rng.choice(game.legal_actions()))
        tricks = [e.trick for e in events if isinstance(e, TrickCompleted)]
        for trick in tricks:
            assert trick.trump_card == trump
            assert TrickResult.from_dict(trick.to_dict()) == trick


@pytest.mark.parametrize("kind", ["wizard", "jester"])
def test_special_trump_card_means_no_trump(kind):
    game = find_game(lambda card: card is not None and card.kind.value == kind)
    obs = game.observation(0)
    assert obs.trump_card == game.round.trump_card
    assert obs.trump_suit is None
    # Bidding starts right away with the player left of the dealer.
    assert game.phase is Phase.BIDDING
    assert game.current_player == 2


def test_sum_of_bids_never_equals_cards_in_hand():
    game = WizardGame(3, seed=11, first_dealer=0)
    game.apply(1, Bid(0))
    game.apply(2, Bid(0))
    assert game.legal_actions(0) == [Bid(0)]  # bidding 1 would make the sum equal 1


def test_hidden_bids():
    game = WizardGame(3, GameOptions(hidden_bids=True), seed=5, first_dealer=0)
    game.apply(1, Bid(1))
    assert game.observation(1).bids[1] == 1
    assert game.observation(2).bids[1] is None
    assert game.observation(2).has_bid[1] is True
    game.apply(2, Bid(0))
    game.apply(0, Bid(1))  # 0 is not allowed: the bids would add up to the 1 card in hand
    assert game.observation(2).bids == (1, 1, 0)


def test_last_round_has_no_trump():
    game = play_random_game(3, seed=7)
    assert game.round.round_number == 20
    assert game.round.trump_card is None


def test_observation_hides_other_hands_and_round_trips():
    game = WizardGame(5, seed=9)
    obs = game.observation(0)
    assert obs.hand == tuple(sorted(game.hand(0), key=lambda c: c.id))
    data = json.loads(json.dumps(obs.to_dict()))
    assert Observation.from_dict(data) == obs


def test_action_round_trip():
    for action in (Bid(3), PlayCard(card_by_id(WIZARD_ID_OFFSET))):
        assert action_from_dict(action.to_dict()) == action
    with pytest.raises(ValueError):
        action_from_dict({"type": "trump", "suit": "red"})
    with pytest.raises(ValueError):
        action_from_dict({"type": "bid", "value": True})
    with pytest.raises(ValueError):
        action_from_dict({"type": "play", "card": 99})


def test_game_finished_event_and_winners():
    game = WizardGame(3, seed=2)
    rng = random.Random(2)
    last_events = []
    while not game.is_finished:
        last_events = game.apply(game.current_player, rng.choice(game.legal_actions()))
    finished = [e for e in last_events if isinstance(e, GameFinished)]
    assert finished and list(finished[0].winners) == game.winners()
    assert game.observation(0).winners == tuple(game.winners())
    assert game.legal_actions() == []


def test_clone_is_independent():
    game = WizardGame(4, seed=4)
    clone = game.clone()
    clone.apply(clone.current_player, clone.legal_actions()[0])
    assert game.observation(0) != clone.observation(0) or game.current_player != clone.current_player