/**
     * Tests whether this file descriptor is open and valid.
     *
     * @return whether the FD is open and valid
     */
    boolean isOpen();

    /**
     * Tests whether this file descriptor was previously open but has become invalid.
     *
     * @return whether the FD was previously open but became invalid
     */
    boolean isStale();

    /**

        try (MockedStatic<PacMac> pacMacMock = mockStatic(PacMac.class)) {
            // Mock the calculateMac method to return a valid checksum
            byte[] mockChecksum = new byte[16];
            pacMacMock.when(() -> PacMac.calculateMac(anyInt(), any(), any())).thenReturn(mockChecksum);

            // Create a minimal valid PAC structure
            ByteArrayOutputStream baos = new ByteArrayOutputStream();

		shouldPass bool
	}{
		// Test cases with invalid bucket names ( Test number 1-4 ).
		{".test", "", ObjectInfo{}, BucketNameInvalid{Bucket: ".test"}, false},
		{"---", "", ObjectInfo{}, BucketNameInvalid{Bucket: "---"}, false},
		{"ad", "", ObjectInfo{}, BucketNameInvalid{Bucket: "ad"}, false},
		// Test cases with valid but non-existing bucket names (Test number 5-6).

            digest1.sign(data, 0, data.length, request, response);

            // Verify with second digest (simulating server verification)
            boolean isValid = digest2.verify(data, 0, data.length, 0, response);

            assertTrue(isValid, "Valid signature should verify correctly");
        }

        @Test
        @DisplayName("Should sign and verify round trip for SMB 2.1")

                    throw new PACDecodingException("Invalid kerberos version");
                }
                break;
            case 1:
                ASN1Integer msgType = ASN1Util.as(ASN1Integer.class, tagged);
                if (!msgType.getValue().equals(new BigInteger(KerberosConstants.KERBEROS_AP_REQ))) {
                    throw new PACDecodingException("Invalid kerberos request");
                }
                break;

              },
              "invalid": {
                "delay": 0,
                "message": "This was marked as invalid and will be closed now. If this is an error, please provide additional details."
              }

			idx, err = strconv.Atoi(pool)
			if err != nil {
				// We didn't find any matching pools, invalid input
				writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errInvalidArgument), r.URL)
				return
			}
		} else {
			idx = globalEndpoints.GetPoolIdx(pool)
			if idx == -1 {
				// We didn't find any matching pools, invalid input
				writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errInvalidArgument), r.URL)
				return
			}

        Throwable cause = new IllegalStateException("Invalid state");
        CommandExecutionException exception = new CommandExecutionException(message, cause);

        assertNotNull(exception);
        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertEquals("Invalid state", exception.getCause().getMessage());

	case reg >= loong64.REG_X0 && reg <= loong64.REG_X31:
		simd_type = loong64.LASX
	default:
		return errors.New("Loong64 extension: invalid LSX/LASX register: " + fmt.Sprintf("%d", reg))
	}

	if isIndex {
		arng_type, ok = loong64ElemExtMap[ext]
		if !ok {
			return errors.New("Loong64 extension: invalid LSX/LASX arrangement type: " + ext)
		}

		a.Reg = loong64.REG_ELEM
		a.Reg += ((reg & loong64.EXT_REG_MASK) << loong64.EXT_REG_SHIFT)

    }

    @DisplayName("Should throw exception for invalid structure size")
    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 2, 4, 8, 15, 17, 32, 64, 65535 })
    void testReadBytesWireFormatInvalidStructureSize(int structureSize) {
        // Given
        byte[] buffer = new byte[256];
        int offset = 0;

        // Write invalid structure size
        SMBUtil.writeInt2(structureSize, buffer, offset);