Test refactoring (#2427)

* Move tests to root with automatic PyCharm import refactoring. This will likely fail some tests

* Changed entry point for a registration test env.

* Move a stray lunar_lander test to tests/envs/...

* black

* Change the version from which importlib_metadata is replaced with importlib.metadata. Also requiring installing importlib_metadata for python 3.8 now.

???????????

* Undo last commit

tests/vector/test_sync_vector_env.py

@@ -0,0 +1,98 @@
+import pytest
+import numpy as np
+
+from gym.spaces import Box, Tuple
+from tests.vector.utils import CustomSpace, make_env, make_custom_space_env
+
+from gym.vector.sync_vector_env import SyncVectorEnv
+
+
+def test_create_sync_vector_env():
+    env_fns = [make_env("CubeCrash-v0", i) for i in range(8)]
+    try:
+        env = SyncVectorEnv(env_fns)
+    finally:
+        env.close()
+
+    assert env.num_envs == 8
+
+
+def test_reset_sync_vector_env():
+    env_fns = [make_env("CubeCrash-v0", i) for i in range(8)]
+    try:
+        env = SyncVectorEnv(env_fns)
+        observations = env.reset()
+    finally:
+        env.close()
+
+    assert isinstance(env.observation_space, Box)
+    assert isinstance(observations, np.ndarray)
+    assert observations.dtype == env.observation_space.dtype
+    assert observations.shape == (8,) + env.single_observation_space.shape
+    assert observations.shape == env.observation_space.shape
+
+
+@pytest.mark.parametrize("use_single_action_space", [True, False])
+def test_step_sync_vector_env(use_single_action_space):
+    env_fns = [make_env("CubeCrash-v0", i) for i in range(8)]
+    try:
+        env = SyncVectorEnv(env_fns)
+        observations = env.reset()
+        if use_single_action_space:
+            actions = [env.single_action_space.sample() for _ in range(8)]
+        else:
+            actions = env.action_space.sample()
+        observations, rewards, dones, _ = env.step(actions)
+    finally:
+        env.close()
+
+    assert isinstance(env.observation_space, Box)
+    assert isinstance(observations, np.ndarray)
+    assert observations.dtype == env.observation_space.dtype
+    assert observations.shape == (8,) + env.single_observation_space.shape
+    assert observations.shape == env.observation_space.shape
+
+    assert isinstance(rewards, np.ndarray)
+    assert isinstance(rewards[0], (float, np.floating))
+    assert rewards.ndim == 1
+    assert rewards.size == 8
+
+    assert isinstance(dones, np.ndarray)
+    assert dones.dtype == np.bool_
+    assert dones.ndim == 1
+    assert dones.size == 8
+
+
+def test_check_observations_sync_vector_env():
+    # CubeCrash-v0 - observation_space: Box(40, 32, 3)
+    env_fns = [make_env("CubeCrash-v0", i) for i in range(8)]
+    # MemorizeDigits-v0 - observation_space: Box(24, 32, 3)
+    env_fns[1] = make_env("MemorizeDigits-v0", 1)
+    with pytest.raises(RuntimeError):
+        env = SyncVectorEnv(env_fns)
+        env.close()
+
+
+def test_custom_space_sync_vector_env():
+    env_fns = [make_custom_space_env(i) for i in range(4)]
+    try:
+        env = SyncVectorEnv(env_fns)
+        reset_observations = env.reset()
+        actions = ("action-2", "action-3", "action-5", "action-7")
+        step_observations, rewards, dones, _ = env.step(actions)
+    finally:
+        env.close()
+
+    assert isinstance(env.single_observation_space, CustomSpace)
+    assert isinstance(env.observation_space, Tuple)
+
+    assert isinstance(reset_observations, tuple)
+    assert reset_observations == ("reset", "reset", "reset", "reset")
+
+    assert isinstance(step_observations, tuple)
+    assert step_observations == (
+        "step(action-2)",
+        "step(action-3)",
+        "step(action-5)",
+        "step(action-7)",
+    )