Correctly exit actors in unit tests (#47)

We had a small bug in the unit tests that some actors were not exited
cleanly, so their event-emitting intervals were still running, and
pytest was showing a warning about an async task being destroyed but
still pending.

This fixes it.

Author: fnesveda

tests/unit/actor/test_actor_env_helpers.py

@@ -48,3 +48,5 @@ async def test_get_env_use_env_vars(self, monkeypatch: pytest.MonkeyPatch) -> No
 
         await Actor.init()
         assert expected_get_env == Actor.get_env()
+
+        await Actor.exit()

tests/unit/actor/test_actor_lifecycle.py

@@ -127,6 +127,9 @@ async def actor_function() -> None:
         # NOTE: Actor didn't call sys.exit() during testing, check if fail was called.
         my_actor.fail.assert_called_with(exit_code=91, _exc_type=type(err), _exc_value=err, _exc_traceback=err.__traceback__)
 
+        # This is necessary to stop the event emitting intervals
+        await my_actor.exit()
+
     async def test_actor_main_method_raise_return_value(self) -> None:
         my_actor = Actor()
         expected_string = 'Hello world'