docstr: Test to make sure basic asychronous calls to remote workers work.
docstr_tok: ["Test","to","make","sure","basic","asychronous","calls","to","remote","workers","work","."]
code: def test_foreach_worker_async(self):
      """Test to make sure basic asychronous calls to remote workers work."""
      ws = WorkerSet(
          env_creator=lambda _: gym.make("CartPole-v1"),
          default_policy_class=RandomPolicy,
          config=AlgorithmConfig().rollouts(num_rollout_workers=2),
          num_workers=2,
      )
  
      # Fired async request against both remote workers.
      self.assertEqual(
          ws.foreach_worker_async(
              lambda w: w.get_policy(DEFAULT_POLICY_ID),
          ),
          2,
      )
  
      remote_results = ws.fetch_ready_async_reqs(timeout_seconds=None)
      self.assertEqual(len(remote_results), 2)
      for p in remote_results:
          # p is in the format of (worker_id, result).
          # First is the id of the remote worker.
          self.assertTrue(p[0] in [1, 2])
          # Next is the actual policy.
          self.assertIsInstance(p[1], RandomPolicy)
  
      ws.stop()
  
file_path: ray/rllib/evaluation/tests/test_worker_set.py
imports: import gymnasium
  import unittest
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.evaluation.worker_set import WorkerSet
  from ray.rllib.examples.policy.random_policy import RandomPolicy
  from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID
label_desc: Use image node_id 5 for calling the TestWorkerSet obj's underlying member method code with example usage: obj.test_foreach_worker_async() without return types