code: def test_taxi_encode_decode():
      env = TaxiEnv()
  
      state, info = env.reset()
      for _ in range(100):
          assert (
              env.encode(*env.decode(state)) == state
          ), f"state={state}, encode(decode(state))={env.encode(*env.decode(state))}"
          state, _, _, _, _ = env.step(env.action_space.sample())
  
file_path: gym/tests/envs/test_env_implementation.py
imports: from typing import Optional
  import numpy
  import pytest
  import gym
  from gym.envs.box2d import BipedalWalker
  from gym.envs.box2d.lunar_lander import demo_heuristic_lander
  from gym.envs.toy_text import TaxiEnv
  from gym.envs.toy_text.frozen_lake import generate_random_map
label_desc: Use image node_id 6 for calling a global function with example usage: test_taxi_encode_decode() without return types