anchor.diff:      expect(callbacks.currentContextRoots, unorderedEquals([projPath]));
       expect(sources, hasLength(4));
       var uris = sources.map((Source source) => source.uri.toString()).toList();
  -    expect(uris, contains((Uri.file(appPath)).toString()));
  +    expect(uris, contains(toUriStr(appPath)));
       expect(uris, contains('package:proj/main.dart'));
       expect(uris, contains('package:proj/src/internal.dart'));
  -    expect(uris, contains((Uri.file(testFilePath)).toString()));
  +    expect(uris, contains(toUriStr(testFilePath)));
     }
   
     void test_setRoots_addFolderWithPubspecAndPackagespecFolders() {
  
positive.code:     expect(callbacks.currentContextRoots, contains(projPath));
      var projSources = callbacks.currentFileSources(projPath);
      expect(projSources, hasLength(1));
      expect(projSources.first.uri.toString(),
          (Uri.file(join(libPath, 'main.dart')).toString()));
  
      expect(callbacks.currentContextRoots, contains(examplePath));
      var exampleSources = callbacks.currentFileSources(examplePath);
      expect(exampleSources, hasLength(1));
      expect(exampleSources.first.uri.toString(),
          (Uri.file(join(examplePath, 'example.dart')).toString()));
    }
  
    void test_setRoots_addFolderWithNestedPubspec() {
  
negative.code: 
      // update .dart_tool/package_config.json
      callbacks.now++;
      modifyFile(
        packageConfigPath,
        (PackageConfigFileBuilder()..add(name: 'my', rootPath: '../'))
            .toContent(toUriStr: toUriStr),
  