Storage entity registry (#16018)

* Split out storage delayed write

* Update code using delayed save

* Fix tests

* Fix typing test

* Add callback decorator

* Migrate entity registry to storage helper

* Make double loading protection easier

* Lint

* Fix tests

* Ordered Dict

tests/components/sensor/test_mqtt.py

@@ -5,13 +5,14 @@ from datetime import timedelta, datetime
 from unittest.mock import patch
 
 import homeassistant.core as ha
-from homeassistant.setup import setup_component
+from homeassistant.setup import setup_component, async_setup_component
 import homeassistant.components.sensor as sensor
 from homeassistant.const import EVENT_STATE_CHANGED, STATE_UNAVAILABLE
 import homeassistant.util.dt as dt_util
 
 from tests.common import mock_mqtt_component, fire_mqtt_message, \
-    assert_setup_component
+    assert_setup_component, async_fire_mqtt_message, \
+    async_mock_mqtt_component
 from tests.common import get_test_home_assistant, mock_component
 
 
@@ -331,27 +332,6 @@ class TestSensorMQTT(unittest.TestCase):
                          state.attributes.get('val'))
         self.assertEqual('100', state.state)
 
-    def test_unique_id(self):
-        """Test unique id option only creates one sensor per unique_id."""
-        assert setup_component(self.hass, sensor.DOMAIN, {
-            sensor.DOMAIN: [{
-                'platform': 'mqtt',
-                'name': 'Test 1',
-                'state_topic': 'test-topic',
-                'unique_id': 'TOTALLY_UNIQUE'
-            }, {
-                'platform': 'mqtt',
-                'name': 'Test 2',
-                'state_topic': 'test-topic',
-                'unique_id': 'TOTALLY_UNIQUE'
-            }]
-        })
-
-        fire_mqtt_message(self.hass, 'test-topic', 'payload')
-        self.hass.block_till_done()
-
-        assert len(self.hass.states.all()) == 1
-
     def test_invalid_device_class(self):
         """Test device_class option with invalid value."""
         with assert_setup_component(0):
@@ -384,3 +364,26 @@ class TestSensorMQTT(unittest.TestCase):
         assert state.attributes['device_class'] == 'temperature'
         state = self.hass.states.get('sensor.test_2')
         assert 'device_class' not in state.attributes
+
+
+async def test_unique_id(hass):
+    """Test unique id option only creates one sensor per unique_id."""
+    await async_mock_mqtt_component(hass)
+    assert await async_setup_component(hass, sensor.DOMAIN, {
+        sensor.DOMAIN: [{
+            'platform': 'mqtt',
+            'name': 'Test 1',
+            'state_topic': 'test-topic',
+            'unique_id': 'TOTALLY_UNIQUE'
+        }, {
+            'platform': 'mqtt',
+            'name': 'Test 2',
+            'state_topic': 'test-topic',
+            'unique_id': 'TOTALLY_UNIQUE'
+        }]
+    })
+
+    async_fire_mqtt_message(hass, 'test-topic', 'payload')
+    await hass.async_block_till_done()
+
+    assert len(hass.states.async_all()) == 1