Handle time zone change in time_date (#106880)

homeassistant/components/time_date/sensor.py

@@ -7,8 +7,8 @@ import logging
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA, SensorEntity
-from homeassistant.const import CONF_DISPLAY_OPTIONS
-from homeassistant.core import CALLBACK_TYPE, HomeAssistant, callback
+from homeassistant.const import CONF_DISPLAY_OPTIONS, EVENT_CORE_CONFIG_UPDATE
+from homeassistant.core import CALLBACK_TYPE, Event, HomeAssistant, callback
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.event import async_track_point_in_utc_time
@@ -107,6 +107,15 @@ class TimeDateSensor(SensorEntity):
 
     async def async_added_to_hass(self) -> None:
         """Set up first update."""
+
+        async def async_update_config(event: Event) -> None:
+            """Handle core config update."""
+            self._update_state_and_setup_listener()
+            self.async_write_ha_state()
+
+        self.async_on_remove(
+            self.hass.bus.async_listen(EVENT_CORE_CONFIG_UPDATE, async_update_config)
+        )
         self._update_state_and_setup_listener()
 
     async def async_will_remove_from_hass(self) -> None:

tests/components/time_date/test_sensor.py

@@ -181,6 +181,31 @@ async def test_states_non_default_timezone(
     state = hass.states.get("sensor.date_time_iso")
     assert state.state == "2020-10-17T12:42:00"
 
+    # Change time zone
+    await hass.config.async_update(time_zone="Europe/Prague")
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.time")
+    assert state.state == "18:42"
+
+    state = hass.states.get("sensor.date")
+    assert state.state == "2020-10-17"
+
+    state = hass.states.get("sensor.time_utc")
+    assert state.state == "16:42"
+
+    state = hass.states.get("sensor.date_time")
+    assert state.state == "2020-10-17, 18:42"
+
+    state = hass.states.get("sensor.date_time_utc")
+    assert state.state == "2020-10-17, 16:42"
+
+    state = hass.states.get("sensor.internet_time")
+    assert state.state == "@738"
+
+    state = hass.states.get("sensor.date_time_iso")
+    assert state.state == "2020-10-17T18:42:00"
+
 
 @patch(
     "homeassistant.components.time_date.sensor.async_track_point_in_utc_time",