Log invalid templates in script delays (#13423)

* Log invalid templates in script delays

* Abort on error

* Remove unused import

homeassistant/helpers/script.py

@@ -97,11 +97,16 @@ class Script():
 
                 delay = action[CONF_DELAY]
 
+                try:
                     if isinstance(delay, template.Template):
                         delay = vol.All(
                             cv.time_period,
                             cv.positive_timedelta)(
                                 delay.async_render(variables))
+                except (TemplateError, vol.Invalid) as ex:
+                    _LOGGER.error("Error rendering '%s' delay template: %s",
+                                  self.name, ex)
+                    break
 
                 unsub = async_track_point_in_utc_time(
                     self.hass, async_script_delay,

tests/helpers/test_script.py

@@ -218,6 +218,32 @@ class TestScriptHelper(unittest.TestCase):
         assert not script_obj.is_running
         assert len(events) == 2
 
+    def test_delay_invalid_template(self):
+        """Test the delay as a template that fails."""
+        event = 'test_event'
+        events = []
+
+        @callback
+        def record_event(event):
+            """Add recorded event to set."""
+            events.append(event)
+
+        self.hass.bus.listen(event, record_event)
+
+        script_obj = script.Script(self.hass, cv.SCRIPT_SCHEMA([
+            {'event': event},
+            {'delay': '{{ invalid_delay }}'},
+            {'delay': {'seconds': 5}},
+            {'event': event}]))
+
+        with mock.patch.object(script, '_LOGGER') as mock_logger:
+            script_obj.run()
+            self.hass.block_till_done()
+            assert mock_logger.error.called
+
+        assert not script_obj.is_running
+        assert len(events) == 1
+
     def test_cancel_while_delay(self):
         """Test the cancelling while the delay is present."""
         event = 'test_event'