StringPiece GetRelativePath(StringPiece absolute_path) {
    return tensorflow::str_util::StripPrefix(absolute_path, root_dir_);
  }

  // Initializes the randomness used to ensure test isolation.
  static void InitializeTestRNG() {
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> distribution;
    rng_val_ = distribution(gen);
  }