Fix entity registry comments (#20357)

homeassistant/helpers/entity_registry.py

@@ -127,8 +127,8 @@ class EntityRegistry:
                 device_id=device_id,
                 # When we changed our slugify algorithm, we invalidated some
                 # stored entity IDs with either a __ or ending in _.
-                # Fix introduced in 0.86 (Jan 23, 2018). Next line can be
-                # removed when we release 1.0 or in 2019.
+                # Fix introduced in 0.86 (Jan 23, 2019). Next line can be
+                # removed when we release 1.0 or in 2020.
                 new_entity_id='.'.join(slugify(part) for part
                                        in entity_id.split('.', 1)))
 

tests/helpers/test_entity_registry.py

@@ -240,6 +240,10 @@ async def test_loading_invalid_entity_id(hass, hass_storage):
                     'entity_id': 'test.invalid_end_',
                     'platform': 'super_platform',
                     'unique_id': 'id-invalid-end',
+                }, {
+                    'entity_id': 'test._invalid_start',
+                    'platform': 'super_platform',
+                    'unique_id': 'id-invalid-start',
                 }
             ]
         }
@@ -256,3 +260,8 @@ async def test_loading_invalid_entity_id(hass, hass_storage):
         'test', 'super_platform', 'id-invalid-end')
 
     assert valid_entity_id(entity_invalid_end.entity_id)
+
+    entity_invalid_start = registry.async_get_or_create(
+        'test', 'super_platform', 'id-invalid-start')
+
+    assert valid_entity_id(entity_invalid_start.entity_id)