assertEquals((byte) 0x7A, b, "Destination should remain unchanged");
        }
    }

    @Test
    @DisplayName("encode() throws when destination too small")
    void encodeThrowsWhenDestinationTooSmall() {
        byte[] src = makeSeq(5);
        Encodable enc = new ByteEncodable(src, 0, 5);
        byte[] dst = new byte[4]; // too small