tests: add type annotations to Smart tests (#1686)

Add type annotations across all 'smart' tests, enabling mypy to check test function bodies, catching type errors that were previously hidden.

tests/smart/modules/test_light_effect.py

@@ -16,7 +16,7 @@ light_effect = parametrize(
 
 
 @light_effect
-async def test_light_effect(dev: Device, mocker: MockerFixture):
+async def test_light_effect(dev: Device, mocker: MockerFixture) -> None:
     """Test light effect."""
     light_effect = dev.modules.get(Module.LightEffect)
     assert isinstance(light_effect, LightEffect)
@@ -46,7 +46,7 @@ async def test_light_effect(dev: Device, mocker: MockerFixture):
 @pytest.mark.parametrize("effect_active", [True, False])
 async def test_light_effect_brightness(
     dev: Device, effect_active: bool, mocker: MockerFixture
-):
+) -> None:
     """Test that light module uses light_effect for brightness when active."""
     light_module = dev.modules[Module.Light]