Fix attribute-defined-outside-init in harmony tests (#119614)

tests/components/harmony/conftest.py

@@ -4,6 +4,7 @@ from unittest.mock import AsyncMock, MagicMock, PropertyMock, patch
 
 from aioharmony.const import ClientCallbackType
 import pytest
+from typing_extensions import Generator
 
 from homeassistant.components.harmony.const import ACTIVITY_POWER_OFF, DOMAIN
 from homeassistant.const import CONF_HOST, CONF_NAME
@@ -46,21 +47,17 @@ IDS_TO_DEVICES = {
 class FakeHarmonyClient:
     """FakeHarmonyClient to mock away network calls."""
 
-    def initialize(
-        self, ip_address: str = "", callbacks: ClientCallbackType = MagicMock()
-    ):
+    _callbacks: ClientCallbackType
+
+    def __init__(self) -> None:
         """Initialize FakeHarmonyClient class to capture callbacks."""
-        # pylint: disable=attribute-defined-outside-init
         self._activity_name = "Watch TV"
         self.close = AsyncMock()
         self.send_commands = AsyncMock()
         self.change_channel = AsyncMock()
         self.sync = AsyncMock()
-        self._callbacks = callbacks
         self.fw_version = "123.456"
 
-        return self
-
     async def connect(self):
         """Connect and call the appropriate callbacks."""
         self._callbacks.connect(None)
@@ -152,20 +149,27 @@ class FakeHarmonyClient:
 
 
 @pytest.fixture
-def harmony_client():
+def harmony_client() -> FakeHarmonyClient:
     """Create the FakeHarmonyClient instance."""
     return FakeHarmonyClient()
 
 
 @pytest.fixture
-def mock_hc(harmony_client):
+def mock_hc(harmony_client: FakeHarmonyClient) -> Generator[None]:
     """Patch the real HarmonyClient with initialization side effect."""
 
+    def _on_create_instance(
+        ip_address: str, callbacks: ClientCallbackType
+    ) -> FakeHarmonyClient:
+        """Set client callbacks on instance creation."""
+        harmony_client._callbacks = callbacks
+        return harmony_client
+
     with patch(
         "homeassistant.components.harmony.data.HarmonyClient",
-        side_effect=harmony_client.initialize,
-    ) as fake:
-        yield fake
+        side_effect=_on_create_instance,
+    ):
+        yield
 
 
 @pytest.fixture