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_childprotection.py

@@ -1,7 +1,7 @@
 import pytest
 
 from kasa import Module
-from kasa.smart.modules import ChildProtection
+from kasa.smart import SmartDevice
 
 from ...device_fixtures import parametrize
 
@@ -19,9 +19,11 @@ child_protection = parametrize(
         ("child_lock", "enabled", bool),
     ],
 )
-async def test_features(dev, feature, prop_name, type):
+async def test_features(
+    dev: SmartDevice, feature: str, prop_name: str, type: type
+) -> None:
     """Test that features are registered and work as expected."""
-    protect: ChildProtection = dev.modules[Module.ChildProtection]
+    protect = dev.modules[Module.ChildProtection]
     assert protect is not None
 
     prop = getattr(protect, prop_name)
@@ -33,9 +35,9 @@ async def test_features(dev, feature, prop_name, type):
 
 
 @child_protection
-async def test_enabled(dev):
+async def test_enabled(dev: SmartDevice) -> None:
     """Test the API."""
-    protect: ChildProtection = dev.modules[Module.ChildProtection]
+    protect = dev.modules[Module.ChildProtection]
     assert protect is not None
 
     assert isinstance(protect.enabled, bool)