tests/test_chess.py

import chess
import pytest

from tools.image_chess import best_move_san, resolve_stockfish


def test_chess_fails_closed_without_engine(monkeypatch):
    monkeypatch.setattr("tools.image_chess.shutil.which", lambda _: None)
    with pytest.raises(RuntimeError, match="Stockfish is required"):
        resolve_stockfish(None)


def test_stockfish_move_is_converted_to_san(monkeypatch):
    class Engine:
        def __enter__(self):
            return self

        def __exit__(self, *args):
            pass

        def play(self, board, limit):
            return type("Result", (), {"move": chess.Move.from_uci("e2e4")})()

    monkeypatch.setattr(
        "tools.image_chess.resolve_stockfish", lambda path=None: "stockfish"
    )
    monkeypatch.setattr("chess.engine.SimpleEngine.popen_uci", lambda path: Engine())
    assert best_move_san(chess.STARTING_FEN) == "e4"