PacDataInputStream pdis = createInputStream(data);
        assertThrows(PACDecodingException.class, () -> pdis.readUnicodeString());
    }

    @Test
    public void testReadString() throws IOException, PACDecodingException {
        // total=4, unused=1, used=2, string="AB"
        byte[] data = new byte[] { 0x04, 0x00, 0x00, 0x00, // total
                0x01, 0x00, 0x00, 0x00, // unused

        byte[] sidBytes = id.toByteArray();
        assertTrue(sidBytes.length > 0);
    }

    @Test
    @DisplayName("Test PacDataInputStream readString method")
    void testReadString() throws Exception {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(baos);

        // Write a valid string structure