def config(tmpdir):
    """
    Return config with

    - a unique temporary sqlite database location
    - a unique nested dict instance that the test can mutate
    """
    return {
        "authentication": {
            "secret_keys": ["SECRET"],
            "providers": [
                {
                    "provider": "toy",
                    "authenticator": "tiled.authenticators:DictionaryAuthenticator",
                    "args": {
                        "users_to_passwords": {"alice": "secret1", "bob": "secret2"}
                    },
                }
            ],
        },
        "database_uri": f"sqlite:///{tmpdir}/tiled.sqlite",
        "trees": [
            {
                "tree": f"{__name__}:tree",
                "path": "/",
            },
        ],
    }