Uptime sensor (#9856)

* Added uptime sensor for homeassistant

* Fixed pylint and flake8 errors

* Made requested changes from PR

- Fixed stale docstrings
- Changed default state to None
- Added ability for user to use hours or days

* Fixed typo

* Added unit_of_measurement check to test

* Converted to async

- Changed tests to work with async

* Minor updates

tests/components/sensor/test_uptime.py

@@ -0,0 +1,88 @@
+"""The tests for the uptime sensor platform."""
+import unittest
+from unittest.mock import patch
+from datetime import timedelta
+
+from homeassistant.util.async import run_coroutine_threadsafe
+from homeassistant.setup import setup_component
+from homeassistant.components.sensor.uptime import UptimeSensor
+from tests.common import get_test_home_assistant
+
+
+class TestUptimeSensor(unittest.TestCase):
+    """Test the uptime sensor."""
+
+    def setUp(self):
+        """Set up things to run when tests begin."""
+        self.hass = get_test_home_assistant()
+
+    def tearDown(self):
+        """Stop everything that was started."""
+        self.hass.stop()
+
+    def test_uptime_min_config(self):
+        """Test minimum uptime configutation."""
+        config = {
+            'sensor': {
+                'platform': 'uptime',
+            }
+        }
+        assert setup_component(self.hass, 'sensor', config)
+
+    def test_uptime_sensor_name_change(self):
+        """Test uptime sensor with different name."""
+        config = {
+            'sensor': {
+                'platform': 'uptime',
+                'name': 'foobar',
+            }
+        }
+        assert setup_component(self.hass, 'sensor', config)
+
+    def test_uptime_sensor_config_hours(self):
+        """Test uptime sensor with hours defined in config."""
+        config = {
+            'sensor': {
+                'platform': 'uptime',
+                'unit_of_measurement': 'hours',
+            }
+        }
+        assert setup_component(self.hass, 'sensor', config)
+
+    def test_uptime_sensor_days_output(self):
+        """Test uptime sensor output data."""
+        sensor = UptimeSensor('test', 'days')
+        self.assertEqual(sensor.unit_of_measurement, 'days')
+        new_time = sensor.initial + timedelta(days=1)
+        with patch('homeassistant.util.dt.now', return_value=new_time):
+            run_coroutine_threadsafe(
+                sensor.async_update(),
+                self.hass.loop
+            ).result()
+            self.assertEqual(sensor.state, 1.00)
+        new_time = sensor.initial + timedelta(days=111.499)
+        with patch('homeassistant.util.dt.now', return_value=new_time):
+            run_coroutine_threadsafe(
+                sensor.async_update(),
+                self.hass.loop
+            ).result()
+            self.assertEqual(sensor.state, 111.50)
+
+    def test_uptime_sensor_hours_output(self):
+        """Test uptime sensor output data."""
+        sensor = UptimeSensor('test', 'hours')
+        self.assertEqual(sensor.unit_of_measurement, 'hours')
+        new_time = sensor.initial + timedelta(hours=16)
+        with patch('homeassistant.util.dt.now', return_value=new_time):
+            run_coroutine_threadsafe(
+                sensor.async_update(),
+                self.hass.loop
+            ).result()
+            self.assertEqual(sensor.state, 16.00)
+        new_time = sensor.initial + timedelta(hours=72.499)
+        with patch('homeassistant.util.dt.now', return_value=new_time):
+            run_coroutine_threadsafe(
+                sensor.async_update(),
+                self.hass.loop
+            ).result()
+            self.assertEqual(sensor.state, 72.50)