anchor.diff:    });
     group('namespaces', () {
       test('default namespace', () {
  -      XmlDocument document = parse('<html xmlns="http://www.w3.org/1999/xhtml">'
  +      XmlDocument document = parse(
  +          '<html xmlns="http://www.w3.org/1999/xhtml">'
             '  <body lang="en"/>'
             '</html>');
         List<XmlNode> nodes = new List.from(document.descendants)..add(document);
  
positive.code:     });
    });
    group('axis', () {
      var bookXml =
          '<book><title lang="en" price="12.00">XML</title><description/></book>';
      var book = parse(bookXml);
      void verifyIterator(Iterable iterable) {
        var iterator = iterable.iterator;
  
negative.code:       var builder = new XmlBuilder();
        builder.element('element', nest: () {
          builder.namespace('http://1.foo.com/', 'foo');
          expect(() => builder.namespace('http://2.foo.com/', 'foo'), throwsArgumentError);
        }, namespace: 'http://1.foo.com/');
        var actual = builder.build().toString();
        var expected = '<foo:element xmlns:foo="http://1.foo.com/" />';
  