Force update support for MQTT sensor (#6492)

tests/components/sensor/test_mqtt.py

@@ -1,8 +1,10 @@
 """The tests for the MQTT sensor platform."""
 import unittest
 
+import homeassistant.core as ha
 from homeassistant.setup import setup_component
 import homeassistant.components.sensor as sensor
+from homeassistant.const import EVENT_STATE_CHANGED
 from tests.common import mock_mqtt_component, fire_mqtt_message
 
 from tests.common import get_test_home_assistant, mock_component
@@ -58,3 +60,60 @@ class TestSensorMQTT(unittest.TestCase):
         state = self.hass.states.get('sensor.test')
 
         self.assertEqual('100', state.state)
+
+    def test_force_update_disabled(self):
+        """Test force update option."""
+        mock_component(self.hass, 'mqtt')
+        assert setup_component(self.hass, sensor.DOMAIN, {
+            sensor.DOMAIN: {
+                'platform': 'mqtt',
+                'name': 'test',
+                'state_topic': 'test-topic',
+                'unit_of_measurement': 'fav unit'
+            }
+        })
+
+        events = []
+
+        @ha.callback
+        def callback(event):
+            events.append(event)
+
+        self.hass.bus.listen(EVENT_STATE_CHANGED, callback)
+
+        fire_mqtt_message(self.hass, 'test-topic', '100')
+        self.hass.block_till_done()
+        self.assertEqual(1, len(events))
+
+        fire_mqtt_message(self.hass, 'test-topic', '100')
+        self.hass.block_till_done()
+        self.assertEqual(1, len(events))
+
+    def test_force_update_enabled(self):
+        """Test force update option."""
+        mock_component(self.hass, 'mqtt')
+        assert setup_component(self.hass, sensor.DOMAIN, {
+            sensor.DOMAIN: {
+                'platform': 'mqtt',
+                'name': 'test',
+                'state_topic': 'test-topic',
+                'unit_of_measurement': 'fav unit',
+                'force_update': True
+            }
+        })
+
+        events = []
+
+        @ha.callback
+        def callback(event):
+            events.append(event)
+
+        self.hass.bus.listen(EVENT_STATE_CHANGED, callback)
+
+        fire_mqtt_message(self.hass, 'test-topic', '100')
+        self.hass.block_till_done()
+        self.assertEqual(1, len(events))
+
+        fire_mqtt_message(self.hass, 'test-topic', '100')
+        self.hass.block_till_done()
+        self.assertEqual(2, len(events))