server.py

    # Need to let the HS build an auth handler and then mess with it
    # because AuthHandler's constructor requires the HS, so we can't make one
    # beforehand and pass it in to the HS's constructor (chicken / egg)
    async def hash(p: str) -> str:
        return hashlib.md5(p.encode("utf8")).hexdigest()

    hs.get_auth_handler().hash = hash  # type: ignore[assignment]

    async def validate_hash(p: str, h: str) -> bool:
        return hashlib.md5(p.encode("utf8")).hexdigest() == h

    hs.get_auth_handler().validate_hash = validate_hash  # type: ignore[assignment]

    # Make the threadpool and database transactions synchronous for testing.
    _make_test_homeserver_synchronous(hs)

    # Load any configured modules into the homeserver
    module_api = hs.get_module_api()
    for module, module_config in hs.config.modules.loaded_modules:
        module(config=module_config, api=module_api)

    load_legacy_spam_checkers(hs)
    load_legacy_third_party_event_rules(hs)
    load_legacy_presence_router(hs)
    load_legacy_password_auth_providers(hs)

    return hs