Make parent attribute on device consistent across iot and smart (#1023)

Both device types now have an internal `_parent` and a public property getter

kasa/device.py

@@ -328,6 +328,11 @@ class Device(ABC):
         """Send a raw query to the device."""
         return await self.protocol.query(request=request)
 
+    @property
+    def parent(self) -> Device | None:
+        """Return the parent on child devices."""
+        return self._parent
+
     @property
     def children(self) -> Sequence[Device]:
         """Returns the child devices."""

kasa/iot/iotstrip.py

@@ -307,10 +307,12 @@ class IotStripPlug(IotPlug):
     The plug inherits (most of) the system information from the parent.
     """
 
+    _parent: IotStrip
+
     def __init__(self, host: str, parent: IotStrip, child_id: str) -> None:
         super().__init__(host)
 
-        self.parent = parent
+        self._parent = parent
         self.child_id = child_id
         self._last_update = parent._last_update
         self._set_sys_info(parent.sys_info)
@@ -380,7 +382,7 @@ class IotStripPlug(IotPlug):
         self, target: str, cmd: str, arg: dict | None = None, child_ids=None
     ) -> Any:
         """Override query helper to include the child_ids."""
-        return await self.parent._query_helper(
+        return await self._parent._query_helper(
             target, cmd, arg, child_ids=[self.child_id]
         )
 
@@ -441,13 +443,15 @@ class IotStripPlug(IotPlug):
     @requires_update
     def model(self) -> str:
         """Return device model for a child socket."""
-        sys_info = self.parent.sys_info
+        sys_info = self._parent.sys_info
         return f"Socket for {sys_info['model']}"
 
     def _get_child_info(self) -> dict:
         """Return the subdevice information for this device."""
-        for plug in self.parent.sys_info["children"]:
+        for plug in self._parent.sys_info["children"]:
             if plug["id"] == self.child_id:
                 return plug
 
-        raise KasaException(f"Unable to find children {self.child_id}")
+        raise KasaException(
+            f"Unable to find children {self.child_id}"
+        )  # pragma: no cover

kasa/tests/test_childdevice.py

@@ -3,12 +3,19 @@ import sys
 
 import pytest
 
+from kasa import Device
 from kasa.device_type import DeviceType
 from kasa.smart.smartchilddevice import SmartChildDevice
 from kasa.smart.smartdevice import NON_HUB_PARENT_ONLY_MODULES
 from kasa.smartprotocol import _ChildProtocolWrapper
 
-from .conftest import parametrize, parametrize_subtract, strip_smart
+from .conftest import (
+    parametrize,
+    parametrize_combine,
+    parametrize_subtract,
+    strip_iot,
+    strip_smart,
+)
 
 has_children_smart = parametrize(
     "has children", component_filter="control_child", protocol_filter={"SMART"}
@@ -18,6 +25,8 @@ hub_smart = parametrize(
 )
 non_hub_parent_smart = parametrize_subtract(has_children_smart, hub_smart)
 
+has_children = parametrize_combine([has_children_smart, strip_iot])
+
 
 @strip_smart
 def test_childdevice_init(dev, dummy_protocol, mocker):
@@ -100,3 +109,14 @@ async def test_parent_only_modules(dev, dummy_protocol, mocker):
     for child in dev.children:
         for module in NON_HUB_PARENT_ONLY_MODULES:
             assert module not in [type(module) for module in child.modules.values()]
+
+
+@has_children
+async def test_parent_property(dev: Device):
+    """Test a child device exposes it's parent."""
+    if not dev.children:
+        pytest.skip(f"Device {dev} fixture does not have any children")
+
+    assert dev.parent is None
+    for child in dev.children:
+        assert child.parent == dev