Implement action feature (#849)

Adds `FeatureType.Action` making it possible to expose features like
"reboot", "test alarm", "pair" etc.

The `attribute_getter` is no longer mandatory, but it will raise an
exception if not defined for other types than actions.
Trying to read returns a static string `<Action>`.
This overloads the `set_value` to call the given callable on any value.

This also fixes the `play` and `stop` coroutines of the alarm module to
await the call.

kasa/feature.py

@@ -17,7 +17,7 @@ class FeatureType(Enum):
     Sensor = auto()
     BinarySensor = auto()
     Switch = auto()
-    Button = auto()
+    Action = auto()
     Number = auto()
 
 
@@ -46,7 +46,7 @@ class Feature:
     #: User-friendly short description
     name: str
     #: Name of the property that allows accessing the value
-    attribute_getter: str | Callable
+    attribute_getter: str | Callable | None = None
     #: Name of the method that allows changing the value
     attribute_setter: str | None = None
     #: Container storing the data, this overrides 'device' for getters
@@ -95,6 +95,11 @@ class Feature:
     @property
     def value(self):
         """Return the current value."""
+        if self.type == FeatureType.Action:
+            return "<Action>"
+        if self.attribute_getter is None:
+            raise ValueError("Not an action and no attribute_getter set")
+
         container = self.container if self.container is not None else self.device
         if isinstance(self.attribute_getter, Callable):
             return self.attribute_getter(container)
@@ -112,6 +117,9 @@ class Feature:
                 )
 
         container = self.container if self.container is not None else self.device
+        if self.type == FeatureType.Action:
+            return await getattr(container, self.attribute_setter)()
+
         return await getattr(container, self.attribute_setter)(value)
 
     def __repr__(self):

kasa/smart/modules/alarmmodule.py

@@ -54,6 +54,24 @@ class AlarmModule(SmartModule):
                 device, "Alarm volume", container=self, attribute_getter="alarm_volume"
             )
         )
+        self._add_feature(
+            Feature(
+                device,
+                "Test alarm",
+                container=self,
+                attribute_setter="play",
+                type=FeatureType.Action,
+            )
+        )
+        self._add_feature(
+            Feature(
+                device,
+                "Stop alarm",
+                container=self,
+                attribute_setter="stop",
+                type=FeatureType.Action,
+            )
+        )
 
     @property
     def alarm_sound(self):
@@ -83,8 +101,8 @@ class AlarmModule(SmartModule):
 
     async def play(self):
         """Play alarm."""
-        return self.call("play_alarm")
+        return await self.call("play_alarm")
 
     async def stop(self):
         """Stop alarm."""
-        return self.call("stop_alarm")
+        return await self.call("stop_alarm")

kasa/tests/test_feature.py

@@ -3,11 +3,13 @@ import pytest
 from kasa import Feature, FeatureType
 
 
+class DummyDevice:
+    pass
+
+
 @pytest.fixture
 def dummy_feature() -> Feature:
     # create_autospec for device slows tests way too much, so we use a dummy here
-    class DummyDevice:
-        pass
 
     feat = Feature(
         device=DummyDevice(),  # type: ignore[arg-type]
@@ -79,3 +81,19 @@ async def test_feature_setter_read_only(dummy_feature):
     dummy_feature.attribute_setter = None
     with pytest.raises(ValueError):
         await dummy_feature.set_value("value for read only feature")
+
+
+async def test_feature_action(mocker):
+    """Test that setting value on button calls the setter."""
+    feat = Feature(
+        device=DummyDevice(),  # type: ignore[arg-type]
+        name="dummy_feature",
+        attribute_setter="call_action",
+        container=None,
+        icon="mdi:dummy",
+        type=FeatureType.Action,
+    )
+    mock_call_action = mocker.patch.object(feat.device, "call_action", create=True)
+    assert feat.value == "<Action>"
+    await feat.set_value(1234)
+    mock_call_action.assert_called()