Add Danfoss Air HRV support (#20138)

* Add support for Danfoss Air HRV systems.

* Correct lint errors after initial commit of Danfoss Air HRV support.

* A couple of lint fixes for danfoss_air.

* Refactor to comply with HA standards.

* Style fix.

* Use wildcard for danfoss_air in .coveragerc.

* Remove config example from header documentation.
Correct import name for platforms.

homeassistant/components/danfoss_air/sensor.py

@@ -0,0 +1,76 @@
+"""
+Support for the for Danfoss Air HRV sensor platform.
+
+For more details about this component, please refer to the documentation at
+https://home-assistant.io/components/sensor.danfoss_air/
+"""
+from homeassistant.components.danfoss_air import DOMAIN \
+     as DANFOSS_AIR_DOMAIN
+from homeassistant.const import TEMP_CELSIUS
+from homeassistant.helpers.entity import Entity
+
+
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """Set up the available Danfoss Air sensors etc."""
+    from pydanfossair.commands import ReadCommand
+
+    data = hass.data[DANFOSS_AIR_DOMAIN]
+
+    sensors = [
+        ["Danfoss Air Exhaust Temperature", TEMP_CELSIUS,
+         ReadCommand.exhaustTemperature],
+        ["Danfoss Air Outdoor Temperature", TEMP_CELSIUS,
+         ReadCommand.outdoorTemperature],
+        ["Danfoss Air Supply Temperature", TEMP_CELSIUS,
+         ReadCommand.supplyTemperature],
+        ["Danfoss Air Extract Temperature", TEMP_CELSIUS,
+         ReadCommand.extractTemperature],
+        ["Danfoss Air Remaining Filter", '%',
+         ReadCommand.filterPercent],
+        ["Danfoss Air Humidity", '%',
+         ReadCommand.humidity]
+        ]
+
+    dev = []
+
+    for sensor in sensors:
+        dev.append(DanfossAir(data, sensor[0], sensor[1], sensor[2]))
+
+    add_devices(dev, True)
+
+
+class DanfossAir(Entity):
+    """Representation of a Sensor."""
+
+    def __init__(self, data, name, sensorUnit, sensorType):
+        """Initialize the sensor."""
+        self._data = data
+        self._name = name
+        self._state = None
+        self._type = sensorType
+        self._unit = sensorUnit
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit of measurement."""
+        return self._unit
+
+    def update(self):
+        """Update the new state of the sensor.
+
+        This is done through the DanfossAir object tthat does the actually
+        communication with the Air CCM.
+        """
+        self._data.update()
+
+        self._state = self._data.get_value(self._type)