throw new CIFSException("token is null but len > 0");
            }
            if (off < 0 || len < 0 || off > token.length || off + len > token.length) {
                throw new CIFSException("invalid offset/length");
            }
            return Arrays.copyOfRange(token, off, off + len);
        }

        @Override
        public String getNetbiosName() {
            return this.nbName;
        }

        }
    }

    /**
     * Asserts that the argument is valid.
     *
     * @param argName
     *            The name of the argument that must not be invalid.
     * @param expression
     *            The precondition.
     * @param description
     *            The description of why the argument is invalid.
     * @throws ClIllegalArgumentException
     *             If {@code expression} is false.

    }

    @DisplayName("Should throw exception for invalid structure size")
    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 2, 3, 5, 10, 100, 65535 })
    void testReadBytesWireFormatInvalidStructureSize(int structureSize) {
        // Given
        byte[] buffer = new byte[256];
        int offset = 0;

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

    }

    @ParameterizedTest
    @NullAndEmptySource
    @DisplayName("Invalid names are skipped; next valid is returned")
    void skipsMalformedNames_thenReturnsValid(String badName) throws Exception {
        // Arrange: first entry is invalid (null or empty), second is valid
        setupParentForUrlCreation();
        StubFileEntry bad = new StubFileEntry(badName, SmbConstants.TYPE_SERVER);

            "user$name" // invalid character
    })
    void testInvalidUsernames(String username) {
        assertThrows(IllegalArgumentException.class, () -> InputValidator.validateUsername(username));
    }

    @Test
    @DisplayName("Test username length validation")
    void testUsernameLengthValidation() {
        String longUsername = "a".repeat(InputValidator.MAX_USERNAME_LENGTH + 1);

    assertFailsToDecode(base64(), "12345", "Invalid input length 5");
    // These have a combination of invalid length, unrecognized characters and wrong padding.
    assertFailsToDecode(base64(), "AB=C", "Unrecognized character: =");
    assertFailsToDecode(base64(), "A=BCD", "Invalid input length 5");
    assertFailsToDecode(base64(), "?", "Invalid input length 1");
  }

  public void testBase64CannotUpperCase() {

        assertEquals(share, shareCap.getValue());
        assertEquals(svc, svcCap.getValue());
    }

    // Edge/invalid inputs: null or empty share/service cause IllegalArgumentException (mocked)
    @ParameterizedTest
    @DisplayName("getSmbTree invalid inputs (null/empty) throw IllegalArgumentException")
    @CsvSource({ ",service", // null share
            " ,service", // empty share

    /**
     * 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();

    /**

            fail("Expected CIFSException");
        } catch (CIFSException e) {
            // Expected
        }

        assertFalse(context.isValid());

        // Further operations on invalid context should fail
        assertThrows(CIFSException.class, () -> {
            preauthService.updatePreauthHash(sessionId, "test".getBytes());
        });
    }

    @Test

        // Protocol errors
        INVALID_PARAMETER("Invalid parameter", ErrorCategory.PROTOCOL, false), NOT_SUPPORTED("Operation not supported",
                ErrorCategory.PROTOCOL, false), INVALID_PROTOCOL("Invalid protocol", ErrorCategory.PROTOCOL,
                        false), MESSAGE_TOO_LARGE("Message too large", ErrorCategory.PROTOCOL, false),