anchor.diff:        var nestedMap = scores.putIfAbsent(
             section, () => new SplayTreeMap<int, CompareLevel>());
   
  -      nestedMap[e.example] = _compareResult(e, verbose, verboseLooseMatch,
  +      nestedMap[e.example] = _compareResult(
  +          baseUrl, e, verbose, verboseLooseMatch,
             extensionSet: extensionSet);
       }
     });
  
positive.code: 
  String indent(String s) => s.splitMapJoin('\n', onNonMatch: (n) => '    $n');
  
  void printVerboseFailure(
      String message, CommonMarkTestCase test, String expected, String actual) {
    print('$message: http://spec.commonmark.org/0.28/#example-${test.example} '
        '@ ${test.section}');
    print('input:');
    print(indent(test.markdown));
  
negative.code:   }
  }
  
  CompareLevel _compareResult(String baseUrl, CommonMarkTestCase expected,
      bool verboseFail, bool verboseLooseMatch,
      {ExtensionSet extensionSet}) {
    String output;
    try {
      output = markdownToHtml(expected.markdown, extensionSet: extensionSet);
    } catch (err, stackTrace) {
      if (verboseFail) {
        printVerboseFailure(baseUrl, 'ERROR', expected, expected.html,
            'Thrown: $err\n$stackTrace');
      }
  
      return CompareLevel.error;
  