Binary sensor for detecting linear trends (#9808)

* Trend sensor now uses linear regression to calculate trend

* Added numpy to trend sensor test requirements

* Added trendline tests

* Trend sensor now has max_samples attribute

* Trend sensor uses utcnow from HA utils

* Trend sensor now completes setup in async_added_to_hass

* Fixed linter issues

* Fixed broken import

* Trend tests make use of max_samples

* Added @asyncio.coroutine decorator to trend update callback

* Update trend.py

tests/components/binary_sensor/test_trend.py

@@ -10,7 +10,7 @@ class TestTrendBinarySensor:
     hass = None
 
     def setup_method(self, method):
-        """Setup things to be run when tests are started."""
+        """Set up things to be run when tests are started."""
         self.hass = get_test_home_assistant()
 
     def teardown_method(self, method):
@@ -38,6 +38,67 @@ class TestTrendBinarySensor:
         state = self.hass.states.get('binary_sensor.test_trend_sensor')
         assert state.state == 'on'
 
+    def test_up_using_trendline(self):
+        """Test up trend using multiple samples and trendline calculation."""
+        assert setup.setup_component(self.hass, 'binary_sensor', {
+            'binary_sensor': {
+                'platform': 'trend',
+                'sensors': {
+                    'test_trend_sensor': {
+                        'entity_id': "sensor.test_state",
+                        'sample_duration': 300,
+                        'min_gradient': 1,
+                        'max_samples': 25,
+                    }
+                }
+            }
+        })
+
+        for val in [1, 0, 2, 3]:
+            self.hass.states.set('sensor.test_state', val)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('binary_sensor.test_trend_sensor')
+        assert state.state == 'on'
+
+        for val in [0, 1, 0, 0]:
+            self.hass.states.set('sensor.test_state', val)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('binary_sensor.test_trend_sensor')
+        assert state.state == 'off'
+
+    def test_down_using_trendline(self):
+        """Test down trend using multiple samples and trendline calculation."""
+        assert setup.setup_component(self.hass, 'binary_sensor', {
+            'binary_sensor': {
+                'platform': 'trend',
+                'sensors': {
+                    'test_trend_sensor': {
+                        'entity_id': "sensor.test_state",
+                        'sample_duration': 300,
+                        'min_gradient': 1,
+                        'max_samples': 25,
+                        'invert': 'Yes'
+                    }
+                }
+            }
+        })
+
+        for val in [3, 2, 3, 1]:
+            self.hass.states.set('sensor.test_state', val)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('binary_sensor.test_trend_sensor')
+        assert state.state == 'on'
+
+        for val in [4, 2, 4, 4]:
+            self.hass.states.set('sensor.test_state', val)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('binary_sensor.test_trend_sensor')
+        assert state.state == 'off'
+
     def test_down(self):
         """Test down trend."""
         assert setup.setup_component(self.hass, 'binary_sensor', {
@@ -59,7 +120,7 @@ class TestTrendBinarySensor:
         state = self.hass.states.get('binary_sensor.test_trend_sensor')
         assert state.state == 'off'
 
-    def test__invert_up(self):
+    def test_invert_up(self):
         """Test up trend with custom message."""
         assert setup.setup_component(self.hass, 'binary_sensor', {
             'binary_sensor': {
@@ -142,11 +203,33 @@ class TestTrendBinarySensor:
         self.hass.states.set('sensor.test_state', 'State', {'attr': '2'})
         self.hass.block_till_done()
         self.hass.states.set('sensor.test_state', 'State', {'attr': '1'})
-
         self.hass.block_till_done()
         state = self.hass.states.get('binary_sensor.test_trend_sensor')
         assert state.state == 'off'
 
+    def test_max_samples(self):
+        """Test that sample count is limited correctly."""
+        assert setup.setup_component(self.hass, 'binary_sensor', {
+            'binary_sensor': {
+                'platform': 'trend',
+                'sensors': {
+                    'test_trend_sensor': {
+                        'entity_id': "sensor.test_state",
+                        'max_samples': 3,
+                        'min_gradient': -1,
+                    }
+                }
+            }
+        })
+
+        for val in [0, 1, 2, 3, 2, 1]:
+            self.hass.states.set('sensor.test_state', val)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('binary_sensor.test_trend_sensor')
+        assert state.state == 'on'
+        assert state.attributes['sample_count'] == 3
+
     def test_non_numeric(self):
         """Test up trend."""
         assert setup.setup_component(self.hass, 'binary_sensor', {
@@ -186,7 +269,6 @@ class TestTrendBinarySensor:
         self.hass.states.set('sensor.test_state', 'State', {'attr': '2'})
         self.hass.block_till_done()
         self.hass.states.set('sensor.test_state', 'State', {'attr': '1'})
-
         self.hass.block_till_done()
         state = self.hass.states.get('binary_sensor.test_trend_sensor')
         assert state.state == 'off'