Make engine testing local

[MarkZH]

Type of pull request:

• Bug fix
• Feature
• Other

Description:

Stops downloading chess engines every time a test is run. All engine types are simulated locally.

Related Issues:

N/A

Checklist:

• I have read and followed the contribution guidelines.
• I have added necessary documentation (if applicable).
• The changes pass all existing tests.

Screenshots/logs (if applicable):

[MarkZH]

Problems so far:

1. Mypy doesn't like the from test_games import scholars_mate in the new engine files: xboard_engine.py, uci_engine.py, buggy_engine.py, and homemade.py.
2. External moves test is failing when lichess.org returns a 429 error.

@AttackingOrDefending, any ideas for fixing (1)? For (2), can we detect connection errors and skip tests?

[AttackingOrDefending]

For (1):
engine_wrapper.py:

def create_engine(engine_config: Configuration, game: model.Game | None = None) -> EngineWrapper:
    """
    Create the engine.

    Use in a with-block to automatically close the engine when exiting the game.

    :param engine_config: The options for the engine.
    :return: An engine. Either UCI, XBoard, or Homemade.
    """
    cfg = engine_config.engine
    engine_path = cfg.name
    engine_type = cfg.protocol
    commands = []
    if cfg.interpreter:
        commands.append(cfg.interpreter)
        commands.extend(cfg.interpreter_options)
    else:
        engine_path = os.path.abspath(os.path.join(cfg.dir, engine_path))
    commands.append(engine_path)
    if cfg.engine_options:
        for k, v in cfg.engine_options.items():
            commands.append(f"--{k}={v}" if v is not None else f"--{k}")

    stderr = None if cfg.silence_stderr else subprocess.DEVNULL

    Engine: type[UCIEngine | XBoardEngine | MinimalEngine]
    if engine_type == "xboard":
        Engine = XBoardEngine
    elif engine_type == "uci":
        Engine = UCIEngine
    elif engine_type == "homemade":
        Engine = get_homemade_engine(cfg.name)
    else:
        raise ValueError(
            f"    Invalid engine type: {engine_type}. Expected xboard, uci, or homemade.")
    options = remove_managed_options(cfg.lookup(f"{engine_type}_options") or Configuration({}))
    logger.debug(f"Starting engine: {commands}")
    return Engine(commands, options, stderr, cfg.draw_or_resign, game, cwd=cfg.working_dir)

test_bot.py:

python = sys.executable  # Otherwise you have to install chess on the global python

...

        CONFIG["engine"]["dir"] = "test_bot"  # can be removed
        CONFIG["engine"]["name"] = "test_bot.uci_engine"
        CONFIG["engine"]["interpreter"] = python
        CONFIG["engine"]["interpreter_options"] = ["-m"]

And change all imports to: from .test_games import scholars_mate

For (2): Yes, just skip them.

[MarkZH]

I ended up using if typing.TYPE_CHECKING: to get around the differences between how Python and Mypy find imports.

Anyway, this is ready for review and/or merging.

[MarkZH]

The external move tests can be fixed in another PR.

[AttackingOrDefending]

I think python = "python" if platform == "win32" else "python3" should be changed to python = sys.executable, as tests hang if chess isn't installed on the global python.