*
   * @param escaper the non-null escaper to test
   */
  public static void assertBasic(Escaper escaper) throws IOException {
    // Escapers operate on characters: no characters, no escaping.
    Assert.assertEquals("", escaper.escape(""));
    // Assert that escapers throw null pointer exceptions.
    try {
      escaper.escape((String) null);

        // Should handle special characters properly
        assertTrue(written > specialPath.length());

        // Check information level
        int actualInfoLevel = SMBUtil.readInt2(buffer, 0);
        assertEquals(0x0101, actualInfoLevel);
    }

    @Test
    void testWriteParametersWithUnicodePath() {
        String unicodePath = "test/文件名.txt"; // Chinese characters

        assertEquals("", testImplementation.getFullUNCPath());
    }

    @Test
    @DisplayName("Test with special characters in paths")
    void testWithSpecialCharacters() {
        // Test path with spaces and special characters
        String specialPath = "/share/folder name/file with spaces & special!@#$%.txt";
        testImplementation.setPath(specialPath);

    }

    /**
     * Encodes a URL by encoding non-URL-safe characters.
     * Uses the request's character encoding if available, otherwise defaults to UTF-8.
     * Only encodes characters that are not considered URL-safe according to CharUtil.
     *
     * @param url the URL to encode
     * @return the encoded URL with non-URL-safe characters properly encoded
     */
    public static String encodeUrl(final String url) {

var errSftpCertWithoutPrincipals = errors.New("certificates without principal(s) are not accepted")

// error returned when group name contains reserved characters

    // A 4n+1 length string is never legal base64().
    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");

        }

        // Check for control characters
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (c < 0x20 && c != '\t' && c != '\r' && c != '\n') {
                failedValidations.incrementAndGet();
                log.warn("{} contains control characters", fieldName);
                throw new SmbException(fieldName + " contains control characters");
            }
        }
    }

        assertNull(exception.getCause());
    }

    public void test_constructor_withSpecialCharacters() {
        // Test with username containing special characters
        String username = "******@****.***";
        FessUserNotFoundException exception = new FessUserNotFoundException(username);

        assertNotNull(exception);

    }

    // Test append with Unicode characters
    public void test_append_unicodeCharacters() {
        StringBuilder buf = new StringBuilder();
        Supplier<Object> supplier = () -> "テスト 测试 테스트 🎉";

        monitorTarget.append(buf, "unicodeKey", supplier);
        // Unicode characters are escaped in JSON format

     *
     * @param ch the characters from the XML document
     * @param start the start position in the character array
     * @param length the number of characters to use from the character array
     * @throws SAXException if a SAX error occurs during character processing
     */
    @Override
    public void characters(final char[] ch, final int start, final int length) throws SAXException {