Gymnasium/gym/envs/tests/spec_list.py

from gym import envs, logger
import os

skip_mujoco = not (os.environ.get('MUJOCO_KEY'))
if not skip_mujoco:
    try:
        import mujoco_py
    except ImportError:
        skip_mujoco = True

def should_skip_env_spec_for_tests(spec):
    # We skip tests for envs that require dependencies or are otherwise
    # troublesome to run frequently
    ep = spec._entry_point
    # Skip mujoco tests for pull request CI
    if skip_mujoco and (ep.startswith('gym.envs.mujoco') or ep.startswith('gym.envs.robotics:')):
        return True
    try:
        import atari_py
    except ImportError:
        if ep.startswith('gym.envs.atari'):
            return True
    try:
        import Box2D
    except ImportError:
        if ep.startswith('gym.envs.box2d'):
            return True

    if (    'GoEnv' in ep or
            'HexEnv' in ep or
            (ep.startswith("gym.envs.atari") and not spec.id.startswith("Pong") and not spec.id.startswith("Seaquest"))
    ):
        logger.warn("Skipping tests for env {}".format(ep))
        return True
    return False

spec_list = [spec for spec in sorted(envs.registry.all(), key=lambda x: x.id) if spec._entry_point is not None and not should_skip_env_spec_for_tests(spec)]