Add unit_of_measurement property for air_quality entity (#33304)

homeassistant/components/air_quality/__init__.py

@@ -2,6 +2,7 @@
 from datetime import timedelta
 import logging
 
+from homeassistant.const import CONCENTRATION_MICROGRAMS_PER_CUBIC_METER
 from homeassistant.helpers.config_validation import (  # noqa: F401
     PLATFORM_SCHEMA,
     PLATFORM_SCHEMA_BASE,
@@ -144,3 +145,8 @@ class AirQualityEntity(Entity):
     def state(self):
         """Return the current state."""
         return self.particulate_matter_2_5
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit of measurement of this entity."""
+        return CONCENTRATION_MICROGRAMS_PER_CUBIC_METER

homeassistant/components/xiaomi_miio/air_quality.py

@@ -5,12 +5,7 @@ from miio import AirQualityMonitor, Device, DeviceException
 import voluptuous as vol
 
 from homeassistant.components.air_quality import PLATFORM_SCHEMA, AirQualityEntity
-from homeassistant.const import (
-    CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
-    CONF_HOST,
-    CONF_NAME,
-    CONF_TOKEN,
-)
+from homeassistant.const import CONF_HOST, CONF_NAME, CONF_TOKEN
 from homeassistant.exceptions import NoEntitySpecifiedError, PlatformNotReady
 import homeassistant.helpers.config_validation as cv
 
@@ -93,7 +88,6 @@ class AirMonitorB1(AirQualityEntity):
         self._device = device
         self._unique_id = unique_id
         self._icon = "mdi:cloud"
-        self._unit_of_measurement = CONCENTRATION_MICROGRAMS_PER_CUBIC_METER
         self._available = None
         self._air_quality_index = None
         self._carbon_dioxide = None
@@ -185,11 +179,6 @@ class AirMonitorB1(AirQualityEntity):
 
         return data
 
-    @property
-    def unit_of_measurement(self):
-        """Return the unit of measurement."""
-        return self._unit_of_measurement
-
 
 class AirMonitorS1(AirMonitorB1):
     """Air Quality class for Xiaomi cgllc.airmonitor.s1 device."""

tests/components/air_quality/test_air_quality.py

@@ -5,6 +5,10 @@ from homeassistant.components.air_quality import (
     ATTR_OZONE,
     ATTR_PM_10,
 )
+from homeassistant.const import (
+    ATTR_UNIT_OF_MEASUREMENT,
+    CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
+)
 from homeassistant.setup import async_setup_component
 
 
@@ -34,3 +38,6 @@ async def test_attributes(hass):
     assert data.get(ATTR_N2O) is None
     assert data.get(ATTR_OZONE) is None
     assert data.get(ATTR_ATTRIBUTION) == "Powered by Home Assistant"
+    assert (
+        data.get(ATTR_UNIT_OF_MEASUREMENT) == CONCENTRATION_MICROGRAMS_PER_CUBIC_METER
+    )