Adding support for a white value (#3338)

* Update __init__.py

addedattribute "WHITE_VALUE" to improve support for RGBW devices

* Update services.yaml

* Update __init__.py

* Update __init__.py

* Update __init__.py

* Update __init__.py

* Update __init__.py

* Update __init__.py

shortened line

* Update __init__.py

* Update __init__.py

* Add mysensors RGBW and light tests

* Activate support for mysensors RGBW devices with support for
	white_value attribute.
* Add white_value support in light demo platform.
* Add tests for white_value and more for light component.
* Add tests for light demo platform.
* Fix import order in check_config.

tests/components/light/test_demo.py

@@ -0,0 +1,57 @@
+"""The tests for the demo light component."""
+# pylint: disable=too-many-public-methods,protected-access
+import unittest
+
+import homeassistant.components.light as light
+
+from tests.common import get_test_home_assistant
+
+ENTITY_LIGHT = 'light.bed_light'
+
+
+class TestDemoClimate(unittest.TestCase):
+    """Test the demo climate hvac."""
+
+    def setUp(self):  # pylint: disable=invalid-name
+        """Setup things to be run when tests are started."""
+        self.hass = get_test_home_assistant()
+        self.assertTrue(light.setup(self.hass, {'light': {
+            'platform': 'demo',
+        }}))
+
+    def tearDown(self):  # pylint: disable=invalid-name
+        """Stop down everything that was started."""
+        self.hass.stop()
+
+    def test_state_attributes(self):
+        """Test light state attributes."""
+        light.turn_on(
+            self.hass, ENTITY_LIGHT, xy_color=(.4, .6), brightness=25)
+        self.hass.pool.block_till_done()
+        state = self.hass.states.get(ENTITY_LIGHT)
+        self.assertTrue(light.is_on(self.hass, ENTITY_LIGHT))
+        self.assertEqual((.4, .6), state.attributes.get(light.ATTR_XY_COLOR))
+        self.assertEqual(25, state.attributes.get(light.ATTR_BRIGHTNESS))
+        self.assertEqual(
+            (82, 91, 0), state.attributes.get(light.ATTR_RGB_COLOR))
+        light.turn_on(
+            self.hass, ENTITY_LIGHT, rgb_color=(251, 252, 253),
+            white_value=254)
+        self.hass.pool.block_till_done()
+        state = self.hass.states.get(ENTITY_LIGHT)
+        self.assertEqual(254, state.attributes.get(light.ATTR_WHITE_VALUE))
+        self.assertEqual(
+            (251, 252, 253), state.attributes.get(light.ATTR_RGB_COLOR))
+        light.turn_on(self.hass, ENTITY_LIGHT, color_temp=400)
+        self.hass.pool.block_till_done()
+        state = self.hass.states.get(ENTITY_LIGHT)
+        self.assertEqual(400, state.attributes.get(light.ATTR_COLOR_TEMP))
+
+    def test_turn_off(self):
+        """Test light turn off method."""
+        light.turn_on(self.hass, ENTITY_LIGHT)
+        self.hass.pool.block_till_done()
+        self.assertTrue(light.is_on(self.hass, ENTITY_LIGHT))
+        light.turn_off(self.hass, ENTITY_LIGHT)
+        self.hass.pool.block_till_done()
+        self.assertFalse(light.is_on(self.hass, ENTITY_LIGHT))