Entity registry (#11979)

* Entity#unique_id defaults to None

* Initial commit entity registry

* Clean up unique_id property

* Lint

* Add tests to entity component

* Lint

* Restore some unique ids

* Spelling

* Remove use of IP address for unique ID

* Add tests

* Add tests

* Fix tests

* Add some docs

* Add one more test

* Fix new test…

homeassistant/components/binary_sensor/bloomsky.py

@@ -50,7 +50,6 @@ class BloomSkySensor(BinarySensorDevice):
         self._device_id = device['DeviceID']
         self._sensor_name = sensor_name
         self._name = '{} {}'.format(device['DeviceName'], sensor_name)
-        self._unique_id = 'bloomsky_binary_sensor {}'.format(self._name)
         self._state = None
 
     @property
@@ -58,11 +57,6 @@ class BloomSkySensor(BinarySensorDevice):
         """Return the name of the BloomSky device and this sensor."""
         return self._name
 
-    @property
-    def unique_id(self):
-        """Return the unique ID for this sensor."""
-        return self._unique_id
-
     @property
     def device_class(self):
         """Return the class of this sensor, from DEVICE_CLASSES."""