// that this test will run on Windows since `tensorflow::io::JoinPath`
      // behaves differently on Windows. `tmp_dir` should be something like
      // `path/to/tmp/dir/`. After joining path, we will have
      // /path/to/tmp/dir/tf_fs_rng_name/`
      root_dir_ = tensorflow::strings::StrCat(
          "/", tmp_dir_,
          tensorflow::strings::StrCat("tf_fs_", rng_val_, "_", test_name), "/");