// Arrange & Act
        SMBSignatureValidationException ex = new SMBSignatureValidationException(msg);

        // Assert
        if (msg == null) {
            assertNull(ex.getMessage(), "Null message should remain null");
        } else {
            assertEquals(msg, ex.getMessage(), "Message should be stored as provided");
        }
        assertNull(ex.getCause(), "Cause should be null for message-only ctor");

        Smb2LeaseKey key = new Smb2LeaseKey(originalBytes);
        byte[] retrievedKey = key.getKey();

        // Modify the retrieved key
        retrievedKey[0] = (byte) 0xFF;

        // Original key should remain unchanged
        assertEquals(0x01, key.getKey()[0]);
    }

    @Test
    @DisplayName("Should create readable string representation")
    void testToString() {

                    mark = si + 1;
                    state = 5;
                }
                break;
            case 5:
                if (ch == '=') {
                    key = str.substring(mark, si).trim();
                    mark = si + 1;
                } else if (ch == ',' || ch == ']') {
                    final String val = str.substring(mark, si).trim();
                    mark = si + 1;

            // FileInputStream does not support mark/reset
            assertFalse(stream.markSupported());

            assertEquals('A', stream.read());
            assertEquals('B', stream.read());

            // Mark is not supported, so calling mark has no effect
            stream.mark(10);

            assertEquals('C', stream.read());

        for (int i = 0; i < len; i++) {
            assertEquals(src[off + i], dst[dstIndex + i], "Byte mismatch at " + i);
        }

        // Assert: bytes before and after region remain unchanged.
        for (int i = 0; i < dstIndex; i++) {
            assertEquals((byte) 0x55, dst[i], "Unexpected change before copy region at " + i);
        }
        for (int i = dstIndex + len; i < dst.length; i++) {

     * This method delegates to {@link FileInputStream#mark(int)}.
     *
     * @param readlimit the maximum limit of bytes that can be read before the mark position becomes invalid
     */
    @Override
    public synchronized void mark(final int readlimit) {
        fileInputStream.mark(readlimit);
    }

    /**
     * Tests if this input stream supports the mark and reset methods.

        // Initial update - should mark as changed
        entry.updateChild(childName, 1024L, 1000L, false, 0x20, 500L, 800L);
        assertTrue(entry.hasChanges());

        // Clear changes to test next scenario
        entry.markComplete();
        assertFalse(entry.hasChanges());

        // Update with same values - should not mark as changed (no actual change)

        if (nonce.length == 12) {
            // For CCM cipher, pad nonce to 16 bytes with zeros
            System.arraycopy(nonce, 0, this.nonce, 0, 12);
            // Last 4 bytes remain zero-initialized
        } else if (nonce.length == 16) {
            // For GCM cipher, use full 16-byte nonce
            System.arraycopy(nonce, 0, this.nonce, 0, 16);
        } else {

     * @param readlimit the maximum limit of bytes that can be read before the mark position becomes invalid
     */
    @Override
    public synchronized void mark(final int readlimit) {
        inputStream.mark(readlimit);
    }

    /**
     * Tests if this input stream supports the mark and reset methods.
     *
     * @return true if this stream instance supports the mark and reset methods; false otherwise
     */
    @Override

                    mark = si + 1;
                    state = 5;
                }
                break;
            case 5:
                if (ch == '=') {
                    key = str.substring(mark, si).trim();
                    mark = si + 1;
                } else if (ch == ',' || ch == ']') {
                    final String val = str.substring(mark, si).trim();