public void decode(final NdrBuffer buf) throws NdrException {
        decode_header(buf);

        if (this.ptype != 12 && this.ptype != 2 && this.ptype != 3 && this.ptype != 13) {
            throw new NdrException("Unexpected ptype: " + this.ptype);
        }

        if (this.ptype == 2 || this.ptype == 3) { /* Response or Fault */
            this.alloc_hint = buf.dec_ndr_long();

    @Override
    public void decode(final NdrBuffer buf) throws NdrException {
        decode_header(buf);

        if (ptype != 12 && ptype != 2 && ptype != 3 && ptype != 13) {
            throw new NdrException("Unexpected ptype: " + ptype);
        }

        if (ptype == 2 || ptype == 3) { /* Response or Fault */
            alloc_hint = buf.dec_ndr_long();
            buf.dec_ndr_short(); /* context id */

        TestMessage m = new TestMessage();
        m.ptype = 0; // Request type
        NdrBuffer buf = new NdrBuffer(new byte[1024], 0);
        m.encode(buf);

        buf.setIndex(0);
        // Decode will throw exception as ptype 0 is not a valid response type
        assertThrows(NdrException.class, () -> m.decode(buf));
    }

    @Test

            // Verify header encoding including ptype
            verify(mockBuffer, times(3)).enc_ndr_small(0); // minor version, ptype (REQUEST=0), and flags (all are 0)
        }

        @Test
        @DisplayName("encode should handle non-REQUEST ptype correctly")
        void testEncodeNonRequestPtype() throws NdrException {
            message.ptype = DcerpcConstants.RPC_PT_RESPONSE; // 2, not 0

        Field ptypeField = DcerpcMessage.class.getDeclaredField("ptype");
        ptypeField.setAccessible(true);
        int ptypeValue = (int) ptypeField.get(request);
        assertEquals(0, ptypeValue, "The 'ptype' field should be initialized to 0.");

        Field flagsField = DcerpcMessage.class.getDeclaredField("flags");
        flagsField.setAccessible(true);

        assertEquals(mockSamArray, msrpc.sam, "The 'sam' field should be initialized with the provided SamrSamArray.");

        // Verify that the 'ptype' field is set to 0
        assertEquals(0, msrpc.getPtype(), "The 'ptype' field should be initialized to 0.");

        // Verify that the 'flags' field is set to DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG

        // When
        MsrpcSamrOpenDomain msrpcSamrOpenDomain = new MsrpcSamrOpenDomain(mockHandle, access, mockSid, mockDomainHandle);

        // Then
        // Verify that ptype is set to 0
        assertEquals(0, msrpcSamrOpenDomain.getPtype(), "ptype should be initialized to 0");

        // Verify that flags are set correctly (DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG)

        assertEquals(mockHandle, lsarClose.handle, "The handle should be initialized correctly.");

        // Verify that the ptype is set to 0
        assertEquals(0, lsarClose.getPtype(), "The ptype should be set to 0.");

        // Verify that the flags are set to the combination of DCERPC_FIRST_FRAG and DCERPC_LAST_FRAG

        // Verify that ptype and flags are set correctly using reflection
        try {
            java.lang.reflect.Field ptypeField = jcifs.dcerpc.DcerpcMessage.class.getDeclaredField("ptype");
            ptypeField.setAccessible(true);
            assertEquals(0, ptypeField.get(msrpcSamrOpenAlias), "ptype should be initialized to 0");

        // We assume if the object is created, the super constructor was called.
        // We can verify the state of the object after construction.

        // Verify ptype and flags are set correctly
        assertEquals(0, policy.getPtype(), "ptype should be 0");
        assertEquals(DcerpcConstants.DCERPC_FIRST_FRAG | DcerpcConstants.DCERPC_LAST_FRAG, policy.getFlags(),
                "flags should be DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG");