### Question:
XMLScriptService implements ScriptService { public static String escapeForAttributeValue(Object content) { return XMLUtils.escapeAttributeValue(Objects.toString(content, null)); } XMLScriptService(); static String escape(Object content); static String escapeForAttributeValue(Object content); static String escapeForElementContent(Object content); static String unescape(Object content); Document createDOMDocument(); Document parse(LSInput source); Document parse(byte[] content); Document parse(String content); Document parse(InputStream stream); String serialize(Node node); String serialize(Node node, boolean withXmlDeclaration); String transform(Source xml, Source xslt); String transform(Document xml, Document xslt); String transform(byte[] xml, byte[] xslt); String transform(String xml, String xslt);  }### Answer:
@Test void escapeForAttributeValue() { assertEquals("&#60;a b=&#39;c&#39;&#62;d&#60;/a&#62;", XMLScriptService.escapeForAttributeValue("<a b='c'>d</a>")); }
@Test void escapeForAttributeValueNull() { assertNull(XMLScriptService.escapeForAttributeValue(null)); }