From ab128983a3599998749020a9525bb83aaa012e38 Mon Sep 17 00:00:00 2001
From: Michael Wyraz <michael@wyraz.de>
Date: Sun, 26 Mar 2017 20:14:22 +0200
Subject: [PATCH] Fix handling of known->unknown state, extended test, fix lint
 errors

---
 homeassistant/components/sensor/min_max.py | 73 +++++++++++-----------
 tests/components/sensor/test_min_max.py    |  8 ++-
 2 files changed, 45 insertions(+), 36 deletions(-)

diff --git a/homeassistant/components/sensor/min_max.py b/homeassistant/components/sensor/min_max.py
index 4e7199d4f42..3e863562777 100644
--- a/homeassistant/components/sensor/min_max.py
+++ b/homeassistant/components/sensor/min_max.py
@@ -65,6 +65,39 @@ def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
     return True
 
 
+def calc_min(sensor_values):
+    """Calculate min value, honoring unknown states."""
+    val = STATE_UNKNOWN
+    for sval in sensor_values:
+        if sval != STATE_UNKNOWN:
+            if val == STATE_UNKNOWN or val > sval:
+                val = sval
+    return val
+
+
+def calc_max(sensor_values):
+    """Calculate max value, honoring unknown states."""
+    val = STATE_UNKNOWN
+    for sval in sensor_values:
+        if sval != STATE_UNKNOWN:
+            if val == STATE_UNKNOWN or val < sval:
+                val = sval
+    return val
+
+
+def calc_mean(sensor_values, round_digits):
+    """Calculate mean value, honoring unknown states."""
+    val = 0
+    count = 0
+    for sval in sensor_values:
+        if sval != STATE_UNKNOWN:
+            val += sval
+            count += 1
+    if count == 0:
+        return STATE_UNKNOWN
+    return round(val/count, round_digits)
+
+
 class MinMaxSensor(Entity):
     """Representation of a min/max sensor."""
 
@@ -91,6 +124,8 @@ class MinMaxSensor(Entity):
         def async_min_max_sensor_state_listener(entity, old_state, new_state):
             """Called when the sensor changes state."""
             if new_state.state is None or new_state.state in STATE_UNKNOWN:
+                self.states[entity] = STATE_UNKNOWN
+                hass.async_add_job(self.async_update_ha_state, True)
                 return
 
             if self._unit_of_measurement is None:
@@ -152,38 +187,6 @@ class MinMaxSensor(Entity):
         """Get the latest data and updates the states."""
         sensor_values = [self.states[k] for k in self._entity_ids
                          if k in self.states]
-        self.min_value = self.calc_min(sensor_values)
-        self.max_value = self.calc_max(sensor_values)
-        self.mean = self.calc_mean(sensor_values)
-
-    # pylint: disable=R0201
-    def calc_min(self, sensor_values):
-        """Calculate min value, honoring unknown states."""
-        val = STATE_UNKNOWN
-        for sval in sensor_values:
-            if sval != STATE_UNKNOWN:
-                if val == STATE_UNKNOWN or val > sval:
-                    val = sval
-        return val
-
-    # pylint: disable=R0201
-    def calc_max(self, sensor_values):
-        """Calculate max value, honoring unknown states."""
-        val = STATE_UNKNOWN
-        for sval in sensor_values:
-            if sval != STATE_UNKNOWN:
-                if val == STATE_UNKNOWN or val < sval:
-                    val = sval
-        return val
-
-    def calc_mean(self, sensor_values):
-        """Calculate mean value, honoring unknown states."""
-        val = 0
-        count = 0
-        for sval in sensor_values:
-            if sval != STATE_UNKNOWN:
-                val += sval
-                count += 1
-        if count == 0:
-            return STATE_UNKNOWN
-        return round(val/count, self._round_digits)
+        self.min_value = calc_min(sensor_values)
+        self.max_value = calc_max(sensor_values)
+        self.mean = calc_mean(sensor_values, self._round_digits)
diff --git a/tests/components/sensor/test_min_max.py b/tests/components/sensor/test_min_max.py
index 1e95eed7108..c19e2b60627 100644
--- a/tests/components/sensor/test_min_max.py
+++ b/tests/components/sensor/test_min_max.py
@@ -196,7 +196,7 @@ class TestMinMaxSensor(unittest.TestCase):
         state = self.hass.states.get('sensor.test_max')
         self.assertEqual(STATE_UNKNOWN, state.state)
 
-        self.hass.states.set(entity_ids[2], self.values[1])
+        self.hass.states.set(entity_ids[1], self.values[1])
         self.hass.block_till_done()
 
         state = self.hass.states.get('sensor.test_max')
@@ -207,3 +207,9 @@ class TestMinMaxSensor(unittest.TestCase):
 
         state = self.hass.states.get('sensor.test_max')
         self.assertNotEqual(STATE_UNKNOWN, state.state)
+
+        self.hass.states.set(entity_ids[1], STATE_UNKNOWN)
+        self.hass.block_till_done()
+
+        state = self.hass.states.get('sensor.test_max')
+        self.assertEqual(STATE_UNKNOWN, state.state)