code: def test_completed_prefetch_yieldsAllComplete(self, rayWaitMock):
      task1 = createMockWorkerAndObjectRef(1)
      task2 = createMockWorkerAndObjectRef(2)
      # Return the second task as complete and the first as pending
      rayWaitMock.return_value = ([2], [1])
  
      pool = TaskPool()
      pool.add(*task1)
      pool.add(*task2)
  
      fetched = list(pool.completed_prefetch())
      self.assertListEqual(fetched, [task2])
  
file_path: ray/rllib/utils/tests/test_taskpool.py
imports: import unittest
  from unittest.mock import patch
  import ray
  from ray.rllib.utils.actors import TaskPool
label_desc: Use image node_id 1 for calling the TaskPoolTest obj's underlying member method code with example usage: obj.test_completed_prefetch_yieldsAllComplete(rayWaitMock) without return types