Fix light group assume behavior (#82)

* Fix light group assume

* Add regression tests

Author: TheJulianJES

tests/test_light.py

@@ -1905,8 +1905,8 @@ async def test_on_with_off_color(
     new=AsyncMock(return_value=[sentinel.data, zcl_f.Status.SUCCESS]),
 )
 @patch(
-    "zha.application.platforms.light.const.ASSUME_UPDATE_GROUP_FROM_CHILD_DELAY",
-    new=0,
+    "zigpy.zcl.clusters.general.LevelControl.request",
+    new=AsyncMock(return_value=[sentinel.data, zcl_f.Status.SUCCESS]),
 )
 @pytest.mark.looptime
 async def test_group_member_assume_state(
@@ -1958,6 +1958,7 @@ async def test_group_member_assume_state(
     # turn on via UI
     await entity.async_turn_on()
     await zha_gateway.async_block_till_done()
+    await asyncio.sleep(1)  # wait for assume debounce
 
     # members also instantly assume STATE_ON
     assert bool(device_1_light_entity.state["on"]) is True
@@ -1967,12 +1968,39 @@ async def test_group_member_assume_state(
     # turn off via UI
     await entity.async_turn_off()
     await zha_gateway.async_block_till_done()
+    await asyncio.sleep(1)
 
     # members also instantly assume STATE_OFF
     assert bool(device_1_light_entity.state["on"]) is False
     assert bool(device_2_light_entity.state["on"]) is False
     assert bool(entity.state["on"]) is False
 
+    # now test members with different state not being overridden
+    # turn on light 1 to brightness 50
+    await device_1_light_entity.async_turn_on(brightness=50)
+    await zha_gateway.async_block_till_done()
+    assert bool(device_1_light_entity.state["on"]) is True
+    assert device_1_light_entity.state["brightness"] == 50
+
+    # turn on light 2 to brightness 100
+    await device_2_light_entity.async_turn_on(brightness=100)
+    await zha_gateway.async_block_till_done()
+    assert bool(device_2_light_entity.state["on"]) is True
+    assert device_2_light_entity.state["brightness"] == 100
+
+    await asyncio.sleep(1)  # wait for assume debounce
+
+    # turn on group, but do not change brightness
+    await entity.async_turn_on(brightness=None)
+    await zha_gateway.async_block_till_done()
+    await asyncio.sleep(1)
+
+    assert entity.state["brightness"] == 75  # average
+
+    # but members do not change unchanged state
+    assert device_1_light_entity.state["brightness"] == 50
+    assert device_2_light_entity.state["brightness"] == 100
+
 
 async def test_light_state_restoration(
     device_light_3,  # pylint: disable=redefined-outer-name

zha/application/platforms/light/__init__.py

@@ -1361,27 +1361,27 @@ def _make_members_assume_group_state(
 
         # check if the parameters were actually updated
         # in the service call before updating members
-        if ATTR_BRIGHTNESS in service_kwargs:  # or off brightness
+        if service_kwargs.get(ATTR_BRIGHTNESS) is not None:  # or off brightness
             update_params[ATTR_BRIGHTNESS] = self._brightness
         elif off_brightness is not None:
             # if we turn on the group light with "off brightness",
             # pass that to the members
             update_params[ATTR_BRIGHTNESS] = off_brightness
 
-        if ATTR_COLOR_TEMP in service_kwargs:
+        if service_kwargs.get(ATTR_COLOR_TEMP) is not None:
             update_params[ATTR_COLOR_MODE] = self._color_mode
             update_params[ATTR_COLOR_TEMP] = self._color_temp
 
-        if ATTR_XY_COLOR in service_kwargs:
+        if service_kwargs.get(ATTR_XY_COLOR) is not None:
             update_params[ATTR_COLOR_MODE] = self._color_mode
             update_params[ATTR_XY_COLOR] = self._xy_color
 
-        if ATTR_HS_COLOR in service_kwargs:
+        if service_kwargs.get(ATTR_HS_COLOR) is not None:
             update_params[ATTR_COLOR_MODE] = self._color_mode
             update_params[ATTR_HS_COLOR] = self._hs_color
 
-        if ATTR_EFFECT in service_kwargs:
-            update_params[ATTR_EFFECT] = self._effect
+        # we always update effect for now, as we don't know if it was set or not
+        update_params[ATTR_EFFECT] = self._effect
 
         for platform_entity in self.group.get_platform_entities(Light.PLATFORM):
             platform_entity._assume_group_state(update_params)