getting some interface to fs

src/Yavsc.Abstract/FileSystem/AbstractFileSystemHelpers.cs

@@ -47,7 +47,6 @@ namespace Yavsc.Helpers
   
         public static UserDirectoryInfo GetUserFiles(string userName, string subdir)
         {
-
             UserDirectoryInfo di = new UserDirectoryInfo(UserFilesDirName, userName, subdir);
             return di;
         }

src/Yavsc.Abstract/FileSystem/UserDirectoryInfo.cs

@@ -28,7 +28,7 @@ namespace Yavsc.ViewModels.UserFiles
             if (string.IsNullOrWhiteSpace(username))
                 throw new NotSupportedException("No user name, no user dir.");
             UserName = username;
-            var finalPath =  username;
+            var finalPath = path == null ? username : Path.Combine(username, path);
             if (!finalPath.IsValidYavscPath())
                 throw new InvalidOperationException(
                     $"File name contains invalid chars ({finalPath})");