assertFalse(CharUtil.isUrlChar('\u001F')); // US
        assertFalse(CharUtil.isUrlChar('\u007F')); // DEL
    }

    public void test_isUrlChar_extendedAscii() {
        // Test extended ASCII characters (not valid URL chars without encoding)
        assertFalse(CharUtil.isUrlChar('\u00A0')); // non-breaking space
        assertFalse(CharUtil.isUrlChar('\u00FF')); // ÿ
    }

                    && (!getFessConfig().isCrawlerDocumentUseSiteEncodingOnEnglish() || "ISO-8859-1".equalsIgnoreCase(encoding)
                            || "US-ASCII".equalsIgnoreCase(encoding))) {
                enc = getFessConfig().getCrawlerDocumentSiteEncoding();
            } else {
                enc = encoding;
            }

            try {

    }

    /**
     * Test encode/decode round trip with various data
     *
     * @throws Exception
     */
    public void testEncodeDecode_RoundTrip() throws Exception {
        // Test with ASCII text
        final String text = "Hello, World!";
        final byte[] textBytes = text.getBytes("UTF-8");
        final String encoded = Base64Util.encode(textBytes);
        final byte[] decoded = Base64Util.decode(encoded);

     */
    public static String defaultString(final String str, final String defaultStr) {
        return str == null ? defaultStr : str;
    }

    /**
     * <p>Checks if the CharSequence contains only ASCII printable characters.</p>
     *
     * <p>{@code null} will return {@code false}.
     * An empty CharSequence (length()=0) will return {@code true}.</p>
     *
     * <pre>