code: def test_opponent_play_random(self):
      self.env = TicTacToeEnvironment(rng=np.random.RandomState(0))
      s = set()
      states = np.array([[0, 1, 2], [0, 0, 0], [0, 0, 0]])
      legal_actions = self.env._legal_actions(states)
  
      # Make sure that each legal action has been played.
      for _ in range(100):
          s.add(self.env._opponent_play(states))
      self.assertEqual(set(legal_actions), s)
  
file_path: agents/tf_agents/environments/examples/tic_tac_toe_environment_test.py
imports: import numpy
  from tf_agents.environments import utils
  from tf_agents.environments.examples.tic_tac_toe_environment import TicTacToeEnvironment
  from tf_agents.trajectories.time_step import StepType
  from tf_agents.trajectories.time_step import TimeStep
  from tf_agents.utils import test_utils
label_desc: Use image node_id 6 for calling the TicTacToeEnvironmentTest obj's underlying member method code with example usage: obj.test_opponent_play_random() without return types