dustbin_mode: add 'off' mode for cleaner downstream impl (#1488)

Adds a new artificial "Off" mode for dustbin_mode,
which will allow avoiding the need to expose both a toggle and a select
in homeassistant.

This changes the behavior of the existing mode selection, as it is not
anymore possible to change the mode without activating the auto
collection.

* Mode is Off, if auto collection has been disabled
* When setting mode to "Off", this will disable the auto collection
* When setting mode to anything else than "Off", the auto collection
will be automatically enabled.

tests/smart/modules/test_dustbin.py

@@ -60,6 +60,25 @@ async def test_dustbin_mode(dev: SmartDevice, mocker: MockerFixture):
         await dustbin.set_mode("invalid")
 
 
+@dustbin
+async def test_dustbin_mode_off(dev: SmartDevice, mocker: MockerFixture):
+    """Test dustbin_mode == Off."""
+    dustbin = next(get_parent_and_child_modules(dev, Module.Dustbin))
+    call = mocker.spy(dustbin, "call")
+
+    auto_collection = dustbin._device.features["dustbin_mode"]
+    await auto_collection.set_value(Mode.Off.name)
+
+    params = dustbin._settings.copy()
+    params["auto_dust_collection"] = False
+
+    call.assert_called_with("setDustCollectionInfo", params)
+
+    await dev.update()
+    assert dustbin.auto_collection is False
+    assert dustbin.mode is Mode.Off.name
+
+
 @dustbin
 async def test_autocollection(dev: SmartDevice, mocker: MockerFixture):
     """Test autocollection switch."""