Add version sensor (#8912)

* Add version sensor

* Set version directly

* Rework tests and fix typo

* Remove additional blank line

homeassistant/components/sensor/version.py

@@ -0,0 +1,55 @@
+"""
+Support for displaying the current version of Home Assistant.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.version/
+"""
+import asyncio
+import logging
+
+import voluptuous as vol
+
+import homeassistant.helpers.config_validation as cv
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import __version__, CONF_NAME
+from homeassistant.helpers.entity import Entity
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = "Current Version"
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+})
+
+
+@asyncio.coroutine
+def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
+    """Set up the Version sensor platform."""
+    name = config.get(CONF_NAME)
+
+    async_add_devices([VersionSensor(name)])
+
+
+class VersionSensor(Entity):
+    """Representation of a Home Assistant version sensor."""
+
+    def __init__(self, name):
+        """Initialize the Version sensor."""
+        self._name = name
+        self._state = __version__
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def should_poll(self):
+        """No polling needed."""
+        return False
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state

tests/components/sensor/test_version.py

@@ -0,0 +1,50 @@
+"""The test for the version sensor platform."""
+import asyncio
+import unittest
+from unittest.mock import patch
+
+from homeassistant.setup import setup_component
+
+from tests.common import get_test_home_assistant
+
+MOCK_VERSION = '10.0'
+
+
+class TestVersionSensor(unittest.TestCase):
+    """Test the Version sensor."""
+
+    def setup_method(self, method):
+        """Set up things to be run when tests are started."""
+        self.hass = get_test_home_assistant()
+
+    def teardown_method(self, method):
+        """Stop everything that was started."""
+        self.hass.stop()
+
+    def test_version_sensor(self):
+        """Test the Version sensor."""
+        config = {
+            'sensor': {
+                'platform': 'version',
+            }
+        }
+
+        assert setup_component(self.hass, 'sensor', config)
+
+    @asyncio.coroutine
+    def test_version(self):
+        """Test the Version sensor."""
+        config = {
+            'sensor': {
+                'platform': 'version',
+                'name': 'test',
+            }
+        }
+
+        with patch('homeassistant.const.__version__', MOCK_VERSION):
+            assert setup_component(self.hass, 'sensor', config)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('sensor.test')
+
+        self.assertEqual(state.state, '10.0')