code: private StringBuilder getXSLTBase() {
          StringBuilder result = new StringBuilder(XML_DECLARATION)
              .append(XMLUnit.getXSLTStart());
          String tmp = result.toString();
          int close = tmp.lastIndexOf('>');
          if (close == -1) {
              close = tmp.length();
          }
          result.insert(close, getNamespaceDeclarations());
          return result;
      }
docs: What every XSL transform needs