anchor.diff:  
     setUpAll(() {
       fs = MemoryFileSystem();
  -    filePath = globals.fs.path.join('lib', 'foo.txt');
  +    filePath = fs.path.join('lib', 'foo.txt');
     });
   
     group('DevFSContent', () {
  
positive.code:     });
  
      testUsingContext('retry uploads when failure', () async {
        final File file = globals.fs.file(globals.fs.path.join(basePath, filePath));
        await file.parent.create(recursive: true);
        file.writeAsBytesSync(<int>[1, 2, 3]);
        // simulate package
  
negative.code: 
      testUsingContext('create dev file system', () async {
        // simulate workspace
        final File file = fs.file(fs.path.join(basePath, filePath));
        await file.parent.create(recursive: true);
        file.writeAsBytesSync(<int>[1, 2, 3]);
  
  