feat: Allow device manager to perform rediscovery of devices (#674)

* feat: Allow device manager to perform rediscovery of devices

This adds an opton to skip the cache, but also supports fallback to the old device list. Adds tests exercising redisocvery and various cache falblack cases on failure.

* chore: Fix pydoc string

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* chore: style cleanup re-raising a bare exception

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* chore: Remove unnecessary assert in test

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: allenporter

roborock/devices/device_manager.py

@@ -15,6 +15,7 @@
     UserData,
 )
 from roborock.devices.device import DeviceReadyCallback, RoborockDevice
+from roborock.exceptions import RoborockException
 from roborock.map.map_parser import MapParserConfig
 from roborock.mqtt.roborock_session import create_lazy_mqtt_session
 from roborock.mqtt.session import MqttSession
@@ -68,12 +69,17 @@ def __init__(
         self._devices: dict[str, RoborockDevice] = {}
         self._mqtt_session = mqtt_session
 
-    async def discover_devices(self) -> list[RoborockDevice]:
+    async def discover_devices(self, prefer_cache: bool = True) -> list[RoborockDevice]:
         """Discover all devices for the logged-in user."""
         cache_data = await self._cache.get()
-        if not cache_data.home_data:
-            _LOGGER.debug("No cached home data found, fetching from API")
-            cache_data.home_data = await self._web_api.get_home_data()
+        if not cache_data.home_data or not prefer_cache:
+            _LOGGER.debug("Fetching home data (prefer_cache=%s)", prefer_cache)
+            try:
+                cache_data.home_data = await self._web_api.get_home_data()
+            except RoborockException as ex:
+                if not cache_data.home_data:
+                    raise
+                _LOGGER.debug("Failed to fetch home data, using cached data: %s", ex)
             await self._cache.set(cache_data)
         home_data = cache_data.home_data
 

tests/devices/test_device_manager.py

@@ -3,6 +3,7 @@
 import asyncio
 import datetime
 from collections.abc import Generator, Iterator
+from typing import Any
 from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
@@ -149,7 +150,8 @@ async def test_create_home_data_api_exception() -> None:
             await api.get_home_data()
 
 
-async def test_cache_logic() -> None:
+@pytest.mark.parametrize(("prefer_cache", "expected_call_count"), [(True, 1), (False, 2)])
+async def test_cache_logic(prefer_cache: bool, expected_call_count: int) -> None:
     """Test that the cache logic works correctly."""
     call_count = 0
 
@@ -167,8 +169,8 @@ async def mock_home_data_with_counter(*args, **kwargs) -> HomeData:
         assert call_count == 1
 
         # Second call should use cache, not increment call_count
-        devices2 = await device_manager.discover_devices()
-        assert call_count == 1  # Should still be 1, not 2
+        devices2 = await device_manager.discover_devices(prefer_cache=prefer_cache)
+        assert call_count == expected_call_count
         assert len(devices2) == 1
 
         await device_manager.close()
@@ -178,6 +180,29 @@ async def mock_home_data_with_counter(*args, **kwargs) -> HomeData:
         await device_manager.close()
 
 
+async def test_home_data_api_fails_with_cache_fallback() -> None:
+    """Test that home data exceptions may still fall back to use the cache when available."""
+
+    cache = InMemoryCache()
+    cache_data = await cache.get()
+    cache_data.home_data = HomeData.from_dict(mock_data.HOME_DATA_RAW)
+    await cache.set(cache_data)
+
+    with patch(
+        "roborock.devices.device_manager.RoborockApiClient.get_home_data_v3",
+        side_effect=RoborockException("Test exception"),
+    ):
+        # This call will skip the API and use the cache
+        device_manager = await create_device_manager(USER_PARAMS, cache=cache)
+
+        # This call will hit the API since we're not preferring the cache
+        # but will fallback to the cache data on exception
+        devices2 = await device_manager.discover_devices(prefer_cache=False)
+        assert len(devices2) == 1
+
+        await device_manager.close()
+
+
 async def test_ready_callback(home_data: HomeData) -> None:
     """Test that the ready callback is invoked when a device connects."""
     ready_devices: list[RoborockDevice] = []
@@ -245,6 +270,74 @@ async def test_start_connect_failure(home_data: HomeData, channel_failure: Mock,
     assert mock_unsub.call_count == 1
 
 
+async def test_rediscover_devices(mock_rpc_channel: AsyncMock) -> None:
+    """Test that we can discover devices multiple times and discover new devices."""
+    raw_devices: list[dict[str, Any]] = mock_data.HOME_DATA_RAW["devices"]
+    assert len(raw_devices) > 0
+    raw_device_1 = raw_devices[0]
+
+    home_data_responses = [
+        HomeData.from_dict(mock_data.HOME_DATA_RAW),
+        # New device added on second call. We make a copy and updated fields to simulate
+        # a new device.
+        HomeData.from_dict(
+            {
+                **mock_data.HOME_DATA_RAW,
+                "devices": [
+                    raw_device_1,
+                    {
+                        **raw_device_1,
+                        "duid": "new_device_duid",
+                        "name": "New Device",
+                        "model": "roborock.newmodel.v1",
+                        "mac": "00:11:22:33:44:55",
+                    },
+                ],
+            }
+        ),
+    ]
+
+    mock_rpc_channel.send_command.side_effect = [
+        [mock_data.APP_GET_INIT_STATUS],
+        mock_data.STATUS,
+        # Device #2
+        [mock_data.APP_GET_INIT_STATUS],
+        mock_data.STATUS,
+    ]
+
+    async def mock_home_data_with_counter(*args, **kwargs) -> HomeData:
+        nonlocal home_data_responses
+        return home_data_responses.pop(0)
+
+    # First call happens during create_device_manager initialization
+    with patch(
+        "roborock.devices.device_manager.RoborockApiClient.get_home_data_v3",
+        side_effect=mock_home_data_with_counter,
+    ):
+        device_manager = await create_device_manager(USER_PARAMS, cache=InMemoryCache())
+        assert len(await device_manager.get_devices()) == 1
+
+        # Second call should use cache and does not add new device
+        await device_manager.discover_devices(prefer_cache=True)
+        assert len(await device_manager.get_devices()) == 1
+
+        # Third call should fetch new home data and add the new device
+        await device_manager.discover_devices(prefer_cache=False)
+        assert len(await device_manager.get_devices()) == 2
+
+        # Verify the two devices exist with correct data
+        device_1 = await device_manager.get_device("abc123")
+        assert device_1 is not None
+        assert device_1.name == "Roborock S7 MaxV"
+
+        new_device = await device_manager.get_device("new_device_duid")
+        assert new_device
+        assert new_device.name == "New Device"
+
+        # Ensure closing again works without error
+        await device_manager.close()
+
+
 @pytest.mark.parametrize(
     ("channel_exception"),
     [

tests/mock_data.py

@@ -2,6 +2,7 @@
 
 import hashlib
 import json
+from typing import Any
 
 # All data is based on a U.S. customer with a Roborock S7 MaxV Ultra
 USER_EMAIL = "user@domain.com"
@@ -119,7 +120,7 @@
         "type": "WORKFLOW",
     }
 ]
-HOME_DATA_RAW = {
+HOME_DATA_RAW: dict[str, Any] = {
     "id": 123456,
     "name": "My Home",
     "lon": None,