From 1626c236dc63bfac501bccb5589af2ef0937972f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 7 Nov 2020 15:51:06 -1000
Subject: [PATCH] Only call utcnow once during a state changed event (#42941)

---
 homeassistant/core.py |  5 ++++-
 tests/test_core.py    | 21 +++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/homeassistant/core.py b/homeassistant/core.py
index 295e813a642..a5dea7fcc5e 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -1180,12 +1180,14 @@ class StateMachine:
         if context is None:
             context = Context()
 
+        now = dt_util.utcnow()
+
         state = State(
             entity_id,
             new_state,
             attributes,
             last_changed,
-            None,
+            now,
             context,
             old_state is None,
         )
@@ -1195,6 +1197,7 @@ class StateMachine:
             {"entity_id": entity_id, "old_state": old_state, "new_state": state},
             EventOrigin.local,
             context,
+            time_fired=now,
         )
 
 
diff --git a/tests/test_core.py b/tests/test_core.py
index 119c0269ba7..a7bd87c650e 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1584,3 +1584,24 @@ async def test_reserving_states(hass):
     assert hass.states.async_available("light.bedroom") is False
     hass.states.async_remove("light.bedroom")
     assert hass.states.async_available("light.bedroom") is True
+
+
+async def test_state_change_events_match_state_time(hass):
+    """Test last_updated and timed_fired only call utcnow once."""
+
+    events = []
+
+    @ha.callback
+    def _event_listener(event):
+        events.append(event)
+
+    hass.bus.async_listen(ha.EVENT_STATE_CHANGED, _event_listener)
+
+    hass.states.async_set("light.bedroom", "on")
+    await hass.async_block_till_done()
+    state = hass.states.get("light.bedroom")
+
+    import pprint
+
+    pprint.pprint(events)
+    assert state.last_updated == events[0].time_fired