from app.fit.crc import fit_crc


def test_empty_crc_is_zero() -> None:
    assert fit_crc(b"") == 0


def test_crc_is_incremental_equivalent() -> None:
    payload = b".FIT-device-metadata"
    assert fit_crc(payload) == fit_crc(memoryview(payload))
    assert 0 <= fit_crc(payload) <= 0xFFFF