code: def test_start(self):
      ttt = ttt_env.TicTacToeEnv(strict=True)
      self.assertFalse(ttt.done)
  
      # At max one move may have been played by the env.
      spaces = ttt_env.get_open_spaces(ttt.board_state)
      num_open_spaces = len(spaces)
      # i.e. either 8 or 9
      self.assertGreater(num_open_spaces, 7)
  
      # Play a move
      observation, reward, done, unused_info = ttt.step(spaces[0])
  
      # The environment should also have played a move.
      spaces = ttt_env.get_open_spaces(observation)
      self.assertEqual(num_open_spaces - 2, len(spaces))
  
      # Since at-max 3 moves have been played, the game can't end.
      self.assertEqual(reward, 0)
      self.assertFalse(done)
  
file_path: tensor2tensor/tensor2tensor/envs/tic_tac_toe_env_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from tensor2tensor.envs import tic_tac_toe_env
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the TicTacToeEnvTest obj's underlying member method code with example usage: obj.test_start() without return types