anchor.diff:      expect(callbacks.currentContextRoots, contains(examplePath));
       var exampleSources = callbacks.currentFileSources(examplePath);
       expect(exampleSources, hasLength(1));
  -    expect(exampleSources.first.uri.toString(),
  -        (Uri.file('$examplePath/example.dart').toString()));
  +    expect(exampleSources.first.uri, toUri('$examplePath/example.dart'));
     }
   
     void test_setRoots_addFolderWithoutPubspec() {
  
positive.code:     var packageConfigPath = '$projPath/.dart_tool/package_config.json';
      var filePath = convertPath('$projPath/bin/main.dart');
  
      resourceProvider.newFile(packageConfigPath, '');
      resourceProvider.newFile(filePath, 'library main;');
  
      manager.setRoots(<String>[projPath], <String>[]);
  
  
negative.code: 
      // update .dart_tool/package_config.json
      callbacks.now++;
      modifyFile(
        packageConfigPath,
        (PackageConfigFileBuilder()..add(name: 'my', rootPath: '../'))
            .toContent(toUriStr: toUriStr),
  