// Test null input
        assertEquals(StringUtil.EMPTY, XmlUtil.escapeXml(null));
    }

    public void test_escapeXml_empty() {
        // Test empty string
        assertEquals("", XmlUtil.escapeXml(""));
    }

    public void test_escapeXml_basic() {
        // Test basic XML escaping
        assertEquals("&lt;tag&gt;value&lt;/tag&gt;", XmlUtil.escapeXml("<tag>value</tag>"));
    }

 * </ul>
 *
 * <h2>Usage Example:</h2>
 * <pre>
 * {@code
 * String escapedXml = XmlUtil.escapeXml("<tag>value</tag>");
 * Map<String, Object> dataMap = XmlUtil.getDataMap(accessResultData);
 * }
 * </pre>
 *
 * <h2>Thread Safety:</h2>
 * <p>
 * This class is thread-safe as it does not maintain any state.
 * </p>
 *
 * <h2>Dependencies:</h2>
 * <ul>

			case '\n':
				dst.WriteByte('n')
			case '\r':
				dst.WriteByte('r')
			case '\t':
				dst.WriteByte('t')
			default:
				// This encodes bytes < 0x20 except for \t, \n and \r.
				// If escapeHTML is set, it also escapes <, >, and &
				// because they can lead to security holes when
				// user-controlled strings are rendered into JSON
				// and served to some browsers.
				dst.WriteString(`u00`)