// Test various long values
        assertEquals("0000000000000000", Hexdump.toHexString(0L, 16));
        assertEquals("00000000000000FF", Hexdump.toHexString(255L, 16));
        assertEquals("FFFFFFFFFFFFFFFF", Hexdump.toHexString(-1L, 16));

        // Test different sizes
        assertEquals("00000000", Hexdump.toHexString(0L, 8));
        assertEquals("12345678", Hexdump.toHexString(0x12345678L, 8));
    }