Gymnasium/tests/testing_env.py

"""Provides a generic testing environment for use in tests with custom reset, step and render functions."""
import types
from typing import Any, Dict, Optional, Tuple, Union

import gymnasium as gym
from gymnasium import spaces
from gymnasium.core import ActType, ObsType
from gymnasium.envs.registration import EnvSpec


def basic_reset_func(
    self,
    *,
    seed: Optional[int] = None,
    options: Optional[dict] = None,
) -> Union[ObsType, Tuple[ObsType, dict]]:
    """A basic reset function that will pass the environment check using random actions from the observation space."""
    super(GenericTestEnv, self).reset(seed=seed)
    self.observation_space.seed(seed)
    return self.observation_space.sample(), {"options": options}


def new_step_func(self, action: ActType) -> Tuple[ObsType, float, bool, bool, dict]:
    """A step function that follows the new step api that will pass the environment check using random actions from the observation space."""
    return self.observation_space.sample(), 0, False, False, {}


def old_step_func(self, action: ActType) -> Tuple[ObsType, float, bool, dict]:
    """A step function that follows the old step api that will pass the environment check using random actions from the observation space."""
    return self.observation_space.sample(), 0, False, {}


def basic_render_func(self):
    """Basic render fn that does nothing."""
    pass


# todo: change all testing environment to this generic class
class GenericTestEnv(gym.Env):
    """A generic testing environment for use in testing with modified environments are required."""

    def __init__(
        self,
        action_space: spaces.Space = spaces.Box(0, 1, (1,)),
        observation_space: spaces.Space = spaces.Box(0, 1, (1,)),
        reset_func: callable = basic_reset_func,
        step_func: callable = new_step_func,
        render_func: callable = basic_render_func,
        metadata: Dict[str, Any] = {"render_modes": []},
        render_mode: Optional[str] = None,
        spec: EnvSpec = EnvSpec(
            "TestingEnv-v0", "testing-env-no-entry-point", max_episode_steps=100
        ),
    ):
        self.metadata = metadata
        self.render_mode = render_mode
        self.spec = spec

        if observation_space is not None:
            self.observation_space = observation_space
        if action_space is not None:
            self.action_space = action_space

        if reset_func is not None:
            self.reset = types.MethodType(reset_func, self)
        if step_func is not None:
            self.step = types.MethodType(step_func, self)
        if render_func is not None:
            self.render = types.MethodType(render_func, self)

    def reset(
        self,
        *,
        seed: Optional[int] = None,
        options: Optional[dict] = None,
    ) -> Union[ObsType, Tuple[ObsType, dict]]:
        # If you need a default working reset function, use `basic_reset_fn` above
        raise NotImplementedError("TestingEnv reset_fn is not set.")

    def step(self, action: ActType) -> Tuple[ObsType, float, bool, dict]:
        raise NotImplementedError("TestingEnv step_fn is not set.")

    def render(self):
        raise NotImplementedError("testingEnv render_fn is not set.")