Fix filter sensor missing window_size argument (#14252)

* missing window_size argument

* test throttle filter configuration

homeassistant/components/sensor/filter.py

@@ -89,6 +89,8 @@ FILTER_TIME_SMA_SCHEMA = FILTER_SCHEMA.extend({
 
 FILTER_THROTTLE_SCHEMA = FILTER_SCHEMA.extend({
     vol.Required(CONF_FILTER_NAME): FILTER_NAME_THROTTLE,
+    vol.Optional(CONF_FILTER_WINDOW_SIZE,
+                 default=DEFAULT_WINDOW_SIZE): vol.Coerce(int),
 })
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({

tests/components/sensor/test_filter.py

@@ -67,6 +67,9 @@ class TestFilterSensor(unittest.TestCase):
                         'filter': 'lowpass',
                         'time_constant': 10,
                         'precision': 2
+                    }, {
+                        'filter': 'throttle',
+                        'window_size': 1
                     }]
             }
         }