Add time created to persistent notifications. (#17121)

* Add time created to persistent notifications.

* UTC

homeassistant/components/persistent_notification/__init__.py

@@ -17,7 +17,9 @@ from homeassistant.loader import bind_hass
 from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers.entity import async_generate_entity_id
 from homeassistant.util import slugify
+import homeassistant.util.dt as dt_util
 
+ATTR_CREATED_AT = 'created_at'
 ATTR_MESSAGE = 'message'
 ATTR_NOTIFICATION_ID = 'notification_id'
 ATTR_TITLE = 'title'
@@ -147,6 +149,7 @@ async def async_setup(hass: HomeAssistant, config: dict) -> Awaitable[bool]:
             ATTR_NOTIFICATION_ID: notification_id,
             ATTR_STATUS: STATUS_UNREAD,
             ATTR_TITLE: title,
+            ATTR_CREATED_AT: dt_util.utcnow(),
         }
 
         hass.bus.async_fire(EVENT_PERSISTENT_NOTIFICATIONS_UPDATED)
@@ -203,8 +206,9 @@ def websocket_get_notifications(
     connection.send_message(
         websocket_api.result_message(msg['id'], [
             {
-                key: data[key] for key in (ATTR_NOTIFICATION_ID, ATTR_MESSAGE,
-                                           ATTR_STATUS, ATTR_TITLE)
+                key: data[key] for key in (ATTR_NOTIFICATION_ID,
+                                           ATTR_MESSAGE, ATTR_STATUS,
+                                           ATTR_TITLE, ATTR_CREATED_AT)
             }
             for data in hass.data[DOMAIN]['notifications'].values()
         ])

tests/components/persistent_notification/test_init.py

@@ -41,6 +41,7 @@ class TestPersistentNotification:
         assert notification['status'] == pn.STATUS_UNREAD
         assert notification['message'] == 'Hello World 2'
         assert notification['title'] == '2 beers'
+        assert notification['created_at'] is not None
         notifications.clear()
 
     def test_create_notification_id(self):
@@ -174,6 +175,7 @@ async def test_ws_get_notifications(hass, hass_ws_client):
     assert notification['message'] == 'test'
     assert notification['title'] is None
     assert notification['status'] == pn.STATUS_UNREAD
+    assert notification['created_at'] is not None
 
     # Mark Read
     await hass.services.async_call(pn.DOMAIN, pn.SERVICE_MARK_READ, {