// We add a random value into `test_dir` to ensures that two consecutive
    // runs are unlikely to clash.
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> distribution;
    std::string rng_val = std::to_string(distribution(gen));
    return tensorflow::io::JoinPath(std::string(test_dir), rng_val);
  } else {
    return "";
  }
}

static std::string* GetTmpDir() {

  }

  // 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);
  }

  static void SetCloudPath(const std::string& cloud_path) {
    cloud_path_ = cloud_path;
    if (cloud_path_.back() == '/') cloud_path_.pop_back();
  }