final Document document = getDocument(data);
        String value = transformer.getSingleNodeValue(document, "//BODY", node -> node);
        assertEquals("aaa", value);

        value = transformer.getSingleNodeValue(document, "//META[@name='keywords']/@content", node -> node);
        assertEquals("bbb", value);

        value = transformer.getSingleNodeValue(document, "//META[@name='keywords']/@content|//BODY", node -> node);