Fire event when core config is updated (#23922)

* Fire event when core config is updated

tests/test_core.py

@@ -23,7 +23,8 @@ from homeassistant.const import (
     __version__, EVENT_STATE_CHANGED, ATTR_FRIENDLY_NAME, CONF_UNIT_SYSTEM,
     ATTR_NOW, EVENT_TIME_CHANGED, EVENT_TIMER_OUT_OF_SYNC, ATTR_SECONDS,
     EVENT_HOMEASSISTANT_STOP, EVENT_HOMEASSISTANT_CLOSE,
-    EVENT_SERVICE_REGISTERED, EVENT_SERVICE_REMOVED, EVENT_CALL_SERVICE)
+    EVENT_SERVICE_REGISTERED, EVENT_SERVICE_REMOVED, EVENT_CALL_SERVICE,
+    EVENT_CORE_CONFIG_UPDATE)
 
 from tests.common import get_test_home_assistant, async_mock_service
 
@@ -871,7 +872,7 @@ class TestConfig(unittest.TestCase):
     # pylint: disable=invalid-name
     def setUp(self):
         """Set up things to be run when tests are started."""
-        self.config = ha.Config()
+        self.config = ha.Config(None)
         assert self.config.config_dir is None
 
     def test_path_with_file(self):
@@ -942,6 +943,32 @@ class TestConfig(unittest.TestCase):
                 self.config.is_allowed_path(None)
 
 
+async def test_event_on_update(hass, hass_storage):
+    """Test that event is fired on update."""
+    events = []
+
+    @ha.callback
+    def callback(event):
+        events.append(event)
+
+    hass.bus.async_listen(EVENT_CORE_CONFIG_UPDATE, callback)
+
+    assert hass.config.latitude != 12
+
+    await hass.config.update(latitude=12)
+    await hass.async_block_till_done()
+
+    assert hass.config.latitude == 12
+    assert len(events) == 1
+    assert events[0].data == {'latitude': 12}
+
+
+def test_bad_timezone_raises_value_error(hass):
+    """Test bad timezone raises ValueError."""
+    with pytest.raises(ValueError):
+        hass.config.set_time_zone('not_a_timezone')
+
+
 @patch('homeassistant.core.monotonic')
 def test_create_timer(mock_monotonic, loop):
     """Test create timer."""