@MockitoSettings(strictness = Strictness.LENIENT)
    class PreauthHashAndEncryption {
        @Test
        @DisplayName("calculatePreauthHash rejects non-SMB2 or missing negotiation")
        void preauthHash_rejectsWhenUnsupported() {
            // Not SMB2
            assertThrows(SmbUnsupportedOperationException.class, () -> transport.calculatePreauthHash(new byte[] { 1 }, 0, 1, null));

            // SMB2 flag set but no negotiation