anchor.diff:    WorkspaceRoot _root;
     WorkspaceRoot get root {
       if (_root == null) {
  -      _root = new MockWorkspaceRoot(location.entry);
  +      _root = new MockWorkspaceRoot(_location.entry);
       }
   
       return _root;
  
positive.code:   return _fileSystemAccess;
  }
  
  Future<ProjectLocationManager> restoreManager(Spark spark) {
    return spark.localPrefs.getValue('projectFolder').then((String folderToken) {
      return fileSystemAccess.restoreManager(spark, folderToken);
  
negative.code: }
  
  /**
   * Provides abstracted access to all filesystem functions.
   */
  class FileSystemAccess {
    ProjectLocationManager _locationManager;
  
    /**
     * The ProjectLocationManager (default location to create new projects) if one
     * has been chosen.
     */
    ProjectLocationManager get locationManager => _locationManager;
  
    LocationResult _location;
  
    ws.WorkspaceRoot _root;
  
    /**
     * The root where all projects are held
     */
    ws.WorkspaceRoot get root {
      if (_root == null) {
        if (_location != null) {
          _root = getRootFor(_location);
        }
      }
  
  