public static XPath buildXPath(NamespaceContext namespaceContext) {
        XPath xPath = XPathFactory.newInstance().newXPath();
        xPath.setNamespaceContext(namespaceContext);
        return xPath;
    }
@Test
    public void testBuildXPathNullPointerExpected() {
        try {
            XmlHelper.buildXPath(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected.
        }
    }