Adds initial test for BaseEnv (#494)

BaseEnv currently is missing unit tests. To address this problem a
initial test class is create using the unittest framework. This test
checks the initialization of an empty BaseEnv for both cpu and cuda
devices. It also checks for proper dimension of action and observation
manager terms.

Finally this adds James Tigue to the contributor list.

- Adds Unit Test

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] I have run all the tests with `./orbit.sh --test` and they pass
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

CONTRIBUTORS.md

@@ -23,6 +23,7 @@ Guidelines for modifications:
 * Farbod Farshidian
 * Hunter Hansen
 * James Smith
+* James Tigue
 * **Mayank Mittal** (maintainer)
 * Nikita Rudin
 * Pascal Roth

source/extensions/omni.isaac.orbit/test/envs/test_base_env.py

+# Copyright (c) 2022-2024, The ORBIT Project Developers.
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+# ignore private usage of variables warning
+# pyright: reportPrivateUsage=none
+
+from __future__ import annotations
+
+"""Launch Isaac Sim Simulator first."""
+
+from omni.isaac.orbit.app import AppLauncher
+
+# Can set this to False to see the GUI for debugging
+HEADLESS = True
+
+# launch omniverse app
+app_launcher = AppLauncher(headless=HEADLESS)
+simulation_app = app_launcher.app
+
+"""Rest everything follows."""
+
+import torch
+import unittest
+
+import omni.usd
+
+from omni.isaac.orbit.envs import BaseEnv, BaseEnvCfg
+from omni.isaac.orbit.scene import InteractiveSceneCfg
+from omni.isaac.orbit.utils import configclass
+
+
+@configclass
+class EmptyActionsCfg:
+    """Action specifications for the environment."""
+
+    pass
+
+
+@configclass
+class EmptySceneCfg(InteractiveSceneCfg):
+    """Configuration for an empty scene."""
+
+    pass
+
+
+def get_empty_base_env_cfg(device: str = "cuda:0", num_envs: int = 1, env_spacing: float = 1.0):
+    """Generate base environment config based on device"""
+
+    @configclass
+    class EmptyEnvCfg(BaseEnvCfg):
+        """Configuration for the empty test environment."""
+
+        # Scene settings
+        scene: EmptySceneCfg = EmptySceneCfg(num_envs=num_envs, env_spacing=env_spacing)
+        # Basic settings
+        actions: EmptyActionsCfg = EmptyActionsCfg()
+
+        def __post_init__(self):
+            """Post initialization."""
+            # step settings
+            self.decimation = 4  # env step every 4 sim steps: 200Hz / 4 = 50Hz
+            # simulation settings
+            self.sim.dt = 0.005  # sim step every 5ms: 200Hz
+            # pass device down from test
+            self.sim.device = device
+
+    return EmptyEnvCfg()
+
+
+class TestBaseEnv(unittest.TestCase):
+    """Test for base env class"""
+
+    """
+    Tests
+    """
+
+    def test_initialization(self):
+        for device in ("cuda:0", "cpu"):
+            with self.subTest(device=device):
+                # create a new stage
+                omni.usd.get_context().new_stage()
+                # create environment
+                env = BaseEnv(cfg=get_empty_base_env_cfg(device=device))
+                # check size of action manager terms
+                self.assertEqual(env.action_manager.total_action_dim, 0)
+                self.assertEqual(len(env.action_manager.active_terms), 0)
+                self.assertEqual(len(env.action_manager.action_term_dim), 0)
+                # check size of observation manager terms
+                self.assertEqual(len(env.observation_manager.active_terms), 0)
+                self.assertEqual(len(env.observation_manager.group_obs_dim), 0)
+                self.assertEqual(len(env.observation_manager.group_obs_term_dim), 0)
+                self.assertEqual(len(env.observation_manager.group_obs_concatenate), 0)
+                # create actions of correct size (1,0)
+                act = torch.randn_like(env.action_manager.action)
+                # step environment to verify setup
+                for _ in range(2):
+                    obs, ext = env.step(action=act)
+                # close the environment
+                env.close()