Fixes warp library access in unit tests (#378)

# Description

Recently, tests were discovered that import from `utils`: `from
omni.isaac.orbit.utils` cause a `ModuleNotFoundError` for `warp` within
a container workflow fail as they weren't starting up the simulation
app.

This PR fixes this issue by setting up simulation app in any tests that
need it.

Fixes #372

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] 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
- [ ] 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

source/extensions/omni.isaac.orbit/test/utils/test_configclass.py

@@ -5,14 +5,29 @@
 
 from __future__ import annotations
 
+# NOTE: While we don't actually use the simulation app in this test, we still need to launch it
+#       because warp is only available in the context of a running simulation
+"""Launch Isaac Sim Simulator first."""
+
+from omni.isaac.orbit.app import AppLauncher
+
+# launch omniverse app
+app_launcher = AppLauncher(headless=True)
+simulation_app = app_launcher.app
+
+"""Rest everything follows."""
+
 import copy
 import os
 import sys
+import traceback
 import unittest
 from dataclasses import MISSING, asdict, field
 from functools import wraps
 from typing import Callable, ClassVar
 
+import carb
+
 from omni.isaac.orbit.utils.configclass import configclass
 from omni.isaac.orbit.utils.dict import class_to_dict, update_class_from_dict
 from omni.isaac.orbit.utils.io import dump_yaml, load_yaml
@@ -696,4 +711,12 @@ class TestConfigClass(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    try:
+        unittest.main()
+    except Exception as err:
+        carb.log_error(err)
+        carb.log_error(traceback.format_exc())
+        raise
+    finally:
+        # close sim app
+        simulation_app.close()

source/extensions/omni.isaac.orbit/test/utils/test_dict.py

@@ -5,8 +5,23 @@
 
 from __future__ import annotations
 
+# NOTE: While we don't actually use the simulation app in this test, we still need to launch it
+#       because warp is only available in the context of a running simulation
+"""Launch Isaac Sim Simulator first."""
+
+from omni.isaac.orbit.app import AppLauncher
+
+# launch omniverse app
+app_launcher = AppLauncher(headless=True)
+simulation_app = app_launcher.app
+
+"""Rest everything follows."""
+
+import traceback
 import unittest
 
+import carb
+
 import omni.isaac.orbit.utils.dict as dict_utils
 
 
@@ -71,4 +86,12 @@ class TestDictUtilities(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    try:
+        unittest.main()
+    except Exception as err:
+        carb.log_error(err)
+        carb.log_error(traceback.format_exc())
+        raise
+    finally:
+        # close sim app
+        simulation_app.close()

source/extensions/omni.isaac.orbit/test/utils/test_string.py

@@ -5,9 +5,24 @@
 
 from __future__ import annotations
 
+# NOTE: While we don't actually use the simulation app in this test, we still need to launch it
+#       because warp is only available in the context of a running simulation
+"""Launch Isaac Sim Simulator first."""
+
+from omni.isaac.orbit.app import AppLauncher
+
+# launch omniverse app
+app_launcher = AppLauncher(headless=True)
+simulation_app = app_launcher.app
+
+"""Rest everything follows."""
+
 import random
+import traceback
 import unittest
 
+import carb
+
 import omni.isaac.orbit.utils.string as string_utils
 
 
@@ -118,4 +133,12 @@ class TestStringUtilities(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    try:
+        unittest.main()
+    except Exception as err:
+        carb.log_error(err)
+        carb.log_error(traceback.format_exc())
+        raise
+    finally:
+        # close sim app
+        simulation_app.close()

source/extensions/omni.isaac.orbit/test/utils/test_timer.py

@@ -5,9 +5,24 @@
 
 from __future__ import annotations
 
+# NOTE: While we don't actually use the simulation app in this test, we still need to launch it
+#       because warp is only available in the context of a running simulation
+"""Launch Isaac Sim Simulator first."""
+
+from omni.isaac.orbit.app import AppLauncher
+
+# launch omniverse app
+app_launcher = AppLauncher(headless=True)
+simulation_app = app_launcher.app
+
+"""Rest everything follows."""
+
 import time
+import traceback
 import unittest
 
+import carb
+
 from omni.isaac.orbit.utils.timer import Timer
 
 
@@ -37,4 +52,12 @@ class TestTimer(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    try:
+        unittest.main()
+    except Exception as err:
+        carb.log_error(err)
+        carb.log_error(traceback.format_exc())
+        raise
+    finally:
+        # close sim app
+        simulation_app.close()