refactor: inherit FakeChannel from Channel Protocol

Author: allenporter

roborock/testing/channel.py

@@ -6,15 +6,17 @@
 """
 
 from collections.abc import Callable
+from typing import Any
 from unittest.mock import AsyncMock, MagicMock
 
+from roborock.devices.transport.channel import Channel
 from roborock.mqtt.health_manager import HealthManager
 from roborock.protocols.v1_protocol import LocalProtocolVersion
 from roborock.roborock_message import RoborockMessage
 
 
-class FakeChannel:
-    """A stateful, in-memory transport simulator.
+class FakeChannel(Channel):
+    """A stateful, in-memory transport simulator implementing the Channel protocol.
 
     It captures all published messages in `published_messages`, maintains a registry
     of active callbacks in `subscribers`, and enables tests or stateful simulators to
@@ -37,6 +39,8 @@ class FakeChannel:
       to simulate the device broadcasting a state change.
     """
 
+    subscribe: Any
+
     def __init__(self, is_local: bool = False):
         """Initialize the fake channel."""
         self.subscribers: list[Callable[[RoborockMessage], None]] = []