assertThrows(NullPointerException.class, () -> new SID((String) null));
        }

        @Test
        @DisplayName("Binary constructor happy path and round-trip via toByteArray")
        void testBinaryConstructorAndToByteArray() {
            // Arrange: revision=1, count=2, identAuth zeros except last byte, subauth 10, 20
            byte[] ident = new byte[] { 0, 0, 0, 0, 0, 5 };