*            e/
   *            f -> /dontdelete
   *      dontdelete/
   *         a
   *         b/
   *         c
   *      symlinktodir -> work/dir
   * </pre>
   */
  static FileSystem newTestFileSystem(Feature... supportedFeatures) throws IOException {
    FileSystem fs =
        Jimfs.newFileSystem(
            Configuration.unix().toBuilder()