Add smartdevice module for smooth transitions (#759)

* Add smart module for smooth transitions

* Fix tests

* Fix linting

kasa/smart/modules/__init__.py

@@ -2,6 +2,13 @@
 from .childdevicemodule import ChildDeviceModule
 from .devicemodule import DeviceModule
 from .energymodule import EnergyModule
+from .lighttransitionmodule import LightTransitionModule
 from .timemodule import TimeModule
 
-__all__ = ["TimeModule", "EnergyModule", "DeviceModule", "ChildDeviceModule"]
+__all__ = [
+    "TimeModule",
+    "EnergyModule",
+    "DeviceModule",
+    "ChildDeviceModule",
+    "LightTransitionModule",
+]

kasa/smart/modules/lighttransitionmodule.py

@@ -0,0 +1,41 @@
+"""Module for smooth light transitions."""
+from typing import TYPE_CHECKING
+
+from ...feature import Feature, FeatureType
+from ..smartmodule import SmartModule
+
+if TYPE_CHECKING:
+    from ..smartdevice import SmartDevice
+
+
+class LightTransitionModule(SmartModule):
+    """Implementation of gradual on/off."""
+
+    REQUIRED_COMPONENT = "on_off_gradually"
+    QUERY_GETTER_NAME = "get_on_off_gradually_info"
+
+    def __init__(self, device: "SmartDevice", module: str):
+        super().__init__(device, module)
+        self._add_feature(
+            Feature(
+                device=device,
+                container=self,
+                name="Smooth transitions",
+                icon="mdi:transition",
+                attribute_getter="enabled",
+                attribute_setter="set_enabled",
+                type=FeatureType.Switch,
+            )
+        )
+
+    def set_enabled(self, enable: bool):
+        """Enable gradual on/off."""
+        return self.call("set_on_off_gradually_info", {"enable": enable})
+
+    @property
+    def enabled(self) -> bool:
+        """Return True if gradual on/off is enabled."""
+        return bool(self.data["enable"])
+
+    def __cli_output__(self):
+        return f"Gradual on/off enabled: {self.enabled}"

kasa/smart/smartdevice.py

@@ -16,6 +16,7 @@
     ChildDeviceModule,
     DeviceModule,
     EnergyModule,
+    LightTransitionModule,
     TimeModule,
 )
 from .smartmodule import SmartModule

kasa/tests/fakeprotocol_smart.py

@@ -46,6 +46,7 @@ def credentials_hash(self):
 
     FIXTURE_MISSING_MAP = {
         "get_wireless_scan_info": ("wireless", {"ap_list": [], "wep_supported": False}),
+        "get_on_off_gradually_info": ("on_off_gradually", {"enable": True}),
     }
 
     async def send(self, request: str):