load the last good state from db if speedtest data is None (#2645)

* load the last good state from db if speedtest data is None

* return if recorder is not available

homeassistant/components/sensor/speedtest.py

@@ -10,6 +10,7 @@ import sys
 from subprocess import check_output, CalledProcessError
 
 import homeassistant.util.dt as dt_util
+from homeassistant.components import recorder
 from homeassistant.components.sensor import DOMAIN
 from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.event import track_time_change
@@ -85,8 +86,20 @@ class SpeedtestSensor(Entity):
         """Get the latest data and update the states."""
         data = self.speedtest_client.data
         if data is None:
-            return
-
+            entity_id = 'sensor.speedtest_' + self._name.lower()
+            states = recorder.get_model('States')
+            try:
+                last_state = recorder.execute(
+                    recorder.query('States').filter(
+                        (states.entity_id == entity_id) &
+                        (states.last_changed == states.last_updated) &
+                        (states.state != 'unknown')
+                    ).order_by(states.state_id.desc()).limit(1))
+            except TypeError:
+                return
+            if not last_state:
+                return
+            self._state = last_state[0].state
         elif self.type == 'ping':
             self._state = data['ping']
         elif self.type == 'download':