Use greek small letter mu "\u03bc" instead of micro sign "\u00B5" for micro unit prefix (alt 1) (#144853)

Co-authored-by: Erik Montnemery <erik@montnemery.com>

homeassistant/components/airgradient/strings.json

@@ -61,7 +61,7 @@
       "display_pm_standard": {
         "name": "Display PM standard",
         "state": {
-          "ugm3": "µg/m³",
+          "ugm3": "μg/m³",
           "us_aqi": "US AQI"
         }
       },

homeassistant/components/bthome/sensor.py

@@ -72,7 +72,7 @@ SENSOR_DESCRIPTIONS = {
         key=str(BTHomeExtendedSensorDeviceClass.CHANNEL),
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    # Conductivity (µS/cm)
+    # Conductivity (μS/cm)
     (
         BTHomeSensorDeviceClass.CONDUCTIVITY,
         Units.CONDUCTIVITY,
@@ -215,7 +215,7 @@ SENSOR_DESCRIPTIONS = {
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
-    # PM10 (µg/m3)
+    # PM10 (μg/m3)
     (
         BTHomeSensorDeviceClass.PM10,
         Units.CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
@@ -225,7 +225,7 @@ SENSOR_DESCRIPTIONS = {
         native_unit_of_measurement=CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    # PM2.5 (µg/m3)
+    # PM2.5 (μg/m3)
     (
         BTHomeSensorDeviceClass.PM25,
         Units.CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
@@ -318,7 +318,7 @@ SENSOR_DESCRIPTIONS = {
         key=str(BTHomeSensorDeviceClass.UV_INDEX),
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    # Volatile organic Compounds (VOC) (µg/m3)
+    # Volatile organic Compounds (VOC) (μg/m3)
     (
         BTHomeSensorDeviceClass.VOLATILE_ORGANIC_COMPOUNDS,
         Units.CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,

homeassistant/components/derivative/__init__.py

@@ -99,6 +99,18 @@ async def async_migrate_entry(hass: HomeAssistant, config_entry: ConfigEntry) ->
                 config_entry, version=1, minor_version=3
             )
 
+        if config_entry.minor_version < 4:
+            # Ensure we use the correct units
+            new_options = {**config_entry.options}
+
+            if new_options.get("unit_prefix") == "\u00b5":
+                # Ensure we use the preferred coding of μ
+                new_options["unit_prefix"] = "\u03bc"
+
+            hass.config_entries.async_update_entry(
+                config_entry, options=new_options, version=1, minor_version=4
+            )
+
     _LOGGER.debug(
         "Migration to configuration version %s.%s successful",
         config_entry.version,

homeassistant/components/derivative/config_flow.py

@@ -36,7 +36,7 @@ from .const import (
 
 UNIT_PREFIXES = [
     selector.SelectOptionDict(value="n", label="n (nano)"),
-    selector.SelectOptionDict(value="µ", label="µ (micro)"),
+    selector.SelectOptionDict(value="μ", label="μ (micro)"),
     selector.SelectOptionDict(value="m", label="m (milli)"),
     selector.SelectOptionDict(value="k", label="k (kilo)"),
     selector.SelectOptionDict(value="M", label="M (mega)"),
@@ -142,7 +142,7 @@ class ConfigFlowHandler(SchemaConfigFlowHandler, domain=DOMAIN):
     options_flow = OPTIONS_FLOW
 
     VERSION = 1
-    MINOR_VERSION = 3
+    MINOR_VERSION = 4
 
     def async_config_entry_title(self, options: Mapping[str, Any]) -> str:
         """Return config entry title."""

homeassistant/components/derivative/sensor.py

@@ -63,7 +63,7 @@ ATTR_SOURCE_ID = "source"
 UNIT_PREFIXES = {
     None: 1,
     "n": 1e-9,
-    "µ": 1e-6,
+    "μ": 1e-6,
     "m": 1e-3,
     "k": 1e3,
     "M": 1e6,

homeassistant/components/emoncms/sensor.py

@@ -157,7 +157,7 @@ SENSORS: dict[str | None, SensorEntityDescription] = {
         native_unit_of_measurement=UnitOfSpeed.METERS_PER_SECOND,
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    "µg/m³": SensorEntityDescription(
+    "μg/m³": SensorEntityDescription(
         key="concentration|microgram_per_cubic_meter",
         translation_key="concentration",
         native_unit_of_measurement=CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,

homeassistant/components/homekit/type_sensors.py

@@ -291,7 +291,7 @@ class NitrogenDioxideSensor(AirQualitySensor):
 class VolatileOrganicCompoundsSensor(AirQualitySensor):
     """Generate a VolatileOrganicCompoundsSensor accessory as VOCs sensor.
 
-    Sensor entity must return VOC in µg/m3.
+    Sensor entity must return VOC in μg/m3.
     """
 
     def create_services(self) -> None:

homeassistant/components/homekit/util.py

@@ -494,7 +494,7 @@ def temperature_to_states(temperature: float, unit: str) -> float:
 
 
 def density_to_air_quality(density: float) -> int:
-    """Map PM2.5 µg/m3 density to HomeKit AirQuality level."""
+    """Map PM2.5 μg/m3 density to HomeKit AirQuality level."""
     if density <= 9:  # US AQI 0-50 (HomeKit: Excellent)
         return 1
     if density <= 35.4:  # US AQI 51-100 (HomeKit: Good)
@@ -507,7 +507,7 @@ def density_to_air_quality(density: float) -> int:
 
 
 def density_to_air_quality_pm10(density: float) -> int:
-    """Map PM10 µg/m3 density to HomeKit AirQuality level."""
+    """Map PM10 μg/m3 density to HomeKit AirQuality level."""
     if density <= 54:  # US AQI 0-50 (HomeKit: Excellent)
         return 1
     if density <= 154:  # US AQI 51-100 (HomeKit: Good)
@@ -520,7 +520,7 @@ def density_to_air_quality_pm10(density: float) -> int:
 
 
 def density_to_air_quality_nitrogen_dioxide(density: float) -> int:
-    """Map nitrogen dioxide µg/m3 to HomeKit AirQuality level."""
+    """Map nitrogen dioxide μg/m3 to HomeKit AirQuality level."""
     if density <= 30:
         return 1
     if density <= 60:
@@ -533,7 +533,7 @@ def density_to_air_quality_nitrogen_dioxide(density: float) -> int:
 
 
 def density_to_air_quality_voc(density: float) -> int:
-    """Map VOCs µg/m3 to HomeKit AirQuality level.
+    """Map VOCs μg/m3 to HomeKit AirQuality level.
 
     The VOC mappings use the IAQ guidelines for Europe released by the WHO (World Health Organization).
     Referenced from Sensirion_Gas_Sensors_SGP3x_TVOC_Concept.pdf

homeassistant/components/mqtt/number.py

@@ -16,6 +16,7 @@ from homeassistant.components.number import (
     NumberMode,
     RestoreNumber,
 )
+from homeassistant.components.sensor import AMBIGUOUS_UNITS
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     CONF_DEVICE_CLASS,
@@ -70,6 +71,12 @@ MQTT_NUMBER_ATTRIBUTES_BLOCKED = frozenset(
 
 def validate_config(config: ConfigType) -> ConfigType:
     """Validate that the configuration is valid, throws if it isn't."""
+    if (
+        CONF_UNIT_OF_MEASUREMENT in config
+        and (unit_of_measurement := config[CONF_UNIT_OF_MEASUREMENT]) in AMBIGUOUS_UNITS
+    ):
+        config[CONF_UNIT_OF_MEASUREMENT] = AMBIGUOUS_UNITS[unit_of_measurement]
+
     if config[CONF_MIN] > config[CONF_MAX]:
         raise vol.Invalid(f"{CONF_MAX} must be >= {CONF_MIN}")
 

homeassistant/components/mqtt/sensor.py

@@ -10,6 +10,7 @@ import voluptuous as vol
 
 from homeassistant.components import sensor
 from homeassistant.components.sensor import (
+    AMBIGUOUS_UNITS,
     CONF_STATE_CLASS,
     DEVICE_CLASS_UNITS,
     DEVICE_CLASSES_SCHEMA,
@@ -133,9 +134,14 @@ def validate_sensor_state_and_device_class_config(config: ConfigType) -> ConfigT
             f"together with state class '{state_class}'"
         )
 
-    if (device_class := config.get(CONF_DEVICE_CLASS)) is None or (
+    if (unit_of_measurement := config.get(CONF_UNIT_OF_MEASUREMENT)) is None:
-        unit_of_measurement := config.get(CONF_UNIT_OF_MEASUREMENT)
+        return config
-    ) is None:
+
+    unit_of_measurement = config[CONF_UNIT_OF_MEASUREMENT] = AMBIGUOUS_UNITS.get(
+        unit_of_measurement, unit_of_measurement
+    )
+
+    if (device_class := config.get(CONF_DEVICE_CLASS)) is None:
         return config
 
     if (

homeassistant/components/number/__init__.py

@@ -31,6 +31,7 @@ from homeassistant.loader import async_suggest_report_issue
 from homeassistant.util.hass_dict import HassKey
 
 from .const import (  # noqa: F401
+    AMBIGUOUS_UNITS,
     ATTR_MAX,
     ATTR_MIN,
     ATTR_STEP,
@@ -368,6 +369,15 @@ class NumberEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             return self.entity_description.native_unit_of_measurement
         return None
 
+    @final
+    @property
+    def __native_unit_of_measurement_compat(self) -> str | None:
+        """Process ambiguous units."""
+        native_unit_of_measurement = self.native_unit_of_measurement
+        return AMBIGUOUS_UNITS.get(
+            native_unit_of_measurement, native_unit_of_measurement
+        )
+
     @property
     @final
     def unit_of_measurement(self) -> str | None:
@@ -375,7 +385,7 @@ class NumberEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         if self._number_option_unit_of_measurement:
             return self._number_option_unit_of_measurement
 
-        native_unit_of_measurement = self.native_unit_of_measurement
+        native_unit_of_measurement = self.__native_unit_of_measurement_compat
         # device_class is checked after native_unit_of_measurement since most
         # of the time we can avoid the device_class check
         if (
@@ -444,7 +454,7 @@ class NumberEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         if device_class not in UNIT_CONVERTERS:
             return value
 
-        native_unit_of_measurement = self.native_unit_of_measurement
+        native_unit_of_measurement = self.__native_unit_of_measurement_compat
         unit_of_measurement = self.unit_of_measurement
         if native_unit_of_measurement != unit_of_measurement:
             if TYPE_CHECKING:
@@ -473,7 +483,7 @@ class NumberEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         if value is None or (device_class := self.device_class) not in UNIT_CONVERTERS:
             return value
 
-        native_unit_of_measurement = self.native_unit_of_measurement
+        native_unit_of_measurement = self.__native_unit_of_measurement_compat
         unit_of_measurement = self.unit_of_measurement
         if native_unit_of_measurement != unit_of_measurement:
             if TYPE_CHECKING:
@@ -496,7 +506,7 @@ class NumberEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             (number_options := self.registry_entry.options.get(DOMAIN))
             and (custom_unit := number_options.get(CONF_UNIT_OF_MEASUREMENT))
             and (device_class := self.device_class) in UNIT_CONVERTERS
-            and self.native_unit_of_measurement
+            and self.__native_unit_of_measurement_compat
             in UNIT_CONVERTERS[device_class].VALID_UNITS
             and custom_unit in UNIT_CONVERTERS[device_class].VALID_UNITS
         ):

homeassistant/components/number/const.py

@@ -9,6 +9,7 @@ import voluptuous as vol
 
 from homeassistant.const import (
     CONCENTRATION_GRAMS_PER_CUBIC_METER,
+    CONCENTRATION_MICROGRAMS_PER_CUBIC_FOOT,
     CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
     CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER,
     CONCENTRATION_PARTS_PER_BILLION,
@@ -136,7 +137,7 @@ class NumberDeviceClass(StrEnum):
     CONDUCTIVITY = "conductivity"
     """Conductivity.
 
-    Unit of measurement: `S/cm`, `mS/cm`, `µS/cm`
+    Unit of measurement: `S/cm`, `mS/cm`, `μS/cm`
     """
 
     CURRENT = "current"
@@ -168,7 +169,7 @@ class NumberDeviceClass(StrEnum):
     DURATION = "duration"
     """Fixed duration.
 
-    Unit of measurement: `d`, `h`, `min`, `s`, `ms`, `µs`
+    Unit of measurement: `d`, `h`, `min`, `s`, `ms`, `μs`
     """
 
     ENERGY = "energy"
@@ -246,25 +247,25 @@ class NumberDeviceClass(StrEnum):
     NITROGEN_DIOXIDE = "nitrogen_dioxide"
     """Amount of NO2.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     NITROGEN_MONOXIDE = "nitrogen_monoxide"
     """Amount of NO.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     NITROUS_OXIDE = "nitrous_oxide"
     """Amount of N2O.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     OZONE = "ozone"
     """Amount of O3.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PH = "ph"
@@ -276,19 +277,19 @@ class NumberDeviceClass(StrEnum):
     PM1 = "pm1"
     """Particulate matter <= 1 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PM10 = "pm10"
     """Particulate matter <= 10 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PM25 = "pm25"
     """Particulate matter <= 2.5 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     POWER_FACTOR = "power_factor"
@@ -365,7 +366,7 @@ class NumberDeviceClass(StrEnum):
     SULPHUR_DIOXIDE = "sulphur_dioxide"
     """Amount of SO2.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     TEMPERATURE = "temperature"
@@ -377,7 +378,7 @@ class NumberDeviceClass(StrEnum):
     VOLATILE_ORGANIC_COMPOUNDS = "volatile_organic_compounds"
     """Amount of VOC.
 
-    Unit of measurement: `µg/m³`, `mg/m³`
+    Unit of measurement: `μg/m³`, `mg/m³`
     """
 
     VOLATILE_ORGANIC_COMPOUNDS_PARTS = "volatile_organic_compounds_parts"
@@ -389,7 +390,7 @@ class NumberDeviceClass(StrEnum):
     VOLTAGE = "voltage"
     """Voltage.
 
-    Unit of measurement: `V`, `mV`, `µV`, `kV`, `MV`
+    Unit of measurement: `V`, `mV`, `μV`, `kV`, `MV`
     """
 
     VOLUME = "volume"
@@ -436,7 +437,7 @@ class NumberDeviceClass(StrEnum):
     Weight is used instead of mass to fit with every day language.
 
     Unit of measurement: `MASS_*` units
-    - SI / metric: `µg`, `mg`, `g`, `kg`
+    - SI / metric: `μg`, `mg`, `g`, `kg`
     - USCS / imperial: `oz`, `lb`
     """
 
@@ -556,3 +557,16 @@ UNIT_CONVERTERS: dict[NumberDeviceClass, type[BaseUnitConverter]] = {
     NumberDeviceClass.TEMPERATURE: TemperatureConverter,
     NumberDeviceClass.VOLUME_FLOW_RATE: VolumeFlowRateConverter,
 }
+
+# We translate units that were using using the legacy coding of μ \u00b5
+# to units using recommended coding of μ \u03bc
+AMBIGUOUS_UNITS: dict[str | None, str] = {
+    "\u00b5Sv/h": "μSv/h",  # aranet: radiation rate
+    "\u00b5S/cm": UnitOfConductivity.MICROSIEMENS_PER_CM,
+    "\u00b5V": UnitOfElectricPotential.MICROVOLT,
+    "\u00b5g/ft³": CONCENTRATION_MICROGRAMS_PER_CUBIC_FOOT,
+    "\u00b5g/m³": CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
+    "\u00b5mol/s⋅m²": "μmol/s⋅m²",  # fyta: light
+    "\u00b5g": UnitOfMass.MICROGRAMS,
+    "\u00b5s": UnitOfTime.MICROSECONDS,
+}

homeassistant/components/prometheus/__init__.py

@@ -366,6 +366,7 @@ class PrometheusMetrics:
 
     @staticmethod
     def _sanitize_metric_name(metric: str) -> str:
+        metric.replace("\u03bc", "\u00b5")
         return "".join(
             [c if c in ALLOWED_METRIC_CHARS else f"u{hex(ord(c))}" for c in metric]
         )
@@ -747,6 +748,9 @@ class PrometheusMetrics:
             PERCENTAGE: "percent",
         }
         default = unit.replace("/", "_per_")
+        # Unit conversion for CONCENTRATION_MICROGRAMS_PER_CUBIC_METER "μg/m³"
+        # "μ" == "\u03bc" but the API uses "\u00b5"
+        default = default.replace("\u03bc", "\u00b5")
         default = default.lower()
         return units.get(unit, default)
 

homeassistant/components/recorder/auto_repairs/schema.py

@@ -261,7 +261,7 @@ def correct_db_schema_precision(
         from ..migration import _modify_columns  # noqa: PLC0415
 
         precision_columns = _get_precision_column_types(table_object)
-        # Attempt to convert timestamp columns to µs precision
+        # Attempt to convert timestamp columns to μs precision
         session_maker = instance.get_session
         engine = instance.engine
         assert engine is not None, "Engine should be set"

homeassistant/components/sensor/__init__.py

@@ -34,6 +34,7 @@ from homeassistant.util.enum import try_parse_enum
 from homeassistant.util.hass_dict import HassKey
 
 from .const import (  # noqa: F401
+    AMBIGUOUS_UNITS,
     ATTR_LAST_RESET,
     ATTR_OPTIONS,
     ATTR_STATE_CLASS,
@@ -314,7 +315,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         return _numeric_state_expected(
             try_parse_enum(SensorDeviceClass, self.device_class),
             self.state_class,
-            self.native_unit_of_measurement,
+            self.__native_unit_of_measurement_compat,
             self.suggested_display_precision,
         )
 
@@ -366,7 +367,8 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         # Make sure we can convert the units
         if (
             (unit_converter := UNIT_CONVERTERS.get(self.device_class)) is None
-            or self.native_unit_of_measurement not in unit_converter.VALID_UNITS
+            or self.__native_unit_of_measurement_compat
+            not in unit_converter.VALID_UNITS
             or suggested_unit_of_measurement not in unit_converter.VALID_UNITS
         ):
             if not self._invalid_suggested_unit_of_measurement_reported:
@@ -387,7 +389,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         if suggested_unit_of_measurement is None:
             # Fallback to unit suggested by the unit conversion rules from device class
             suggested_unit_of_measurement = self.hass.config.units.get_converted_unit(
-                self.device_class, self.native_unit_of_measurement
+                self.device_class, self.__native_unit_of_measurement_compat
             )
 
         if suggested_unit_of_measurement is None and (
@@ -396,7 +398,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             # If the device class is not known by the unit system but has a unit converter,
             # fall back to the unit suggested by the unit converter's unit class.
             suggested_unit_of_measurement = self.hass.config.units.get_converted_unit(
-                unit_converter.UNIT_CLASS, self.native_unit_of_measurement
+                unit_converter.UNIT_CLASS, self.__native_unit_of_measurement_compat
             )
 
         if suggested_unit_of_measurement is None:
@@ -468,6 +470,16 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             return self.entity_description.native_unit_of_measurement
         return None
 
+    @final
+    @property
+    def __native_unit_of_measurement_compat(self) -> str | None:
+        """Process ambiguous units."""
+        native_unit_of_measurement = self.native_unit_of_measurement
+        return AMBIGUOUS_UNITS.get(
+            native_unit_of_measurement,
+            native_unit_of_measurement,
+        )
+
     @cached_property
     def suggested_unit_of_measurement(self) -> str | None:
         """Return the unit which should be used for the sensor's state.
@@ -503,7 +515,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
         if self._sensor_option_unit_of_measurement is not UNDEFINED:
             return self._sensor_option_unit_of_measurement
 
-        native_unit_of_measurement = self.native_unit_of_measurement
+        native_unit_of_measurement = self.__native_unit_of_measurement_compat
 
         # Second priority, for non registered entities: unit suggested by integration
         if not self.registry_entry and (
@@ -543,7 +555,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
     @override
     def state(self) -> Any:
         """Return the state of the sensor and perform unit conversions, if needed."""
-        native_unit_of_measurement = self.native_unit_of_measurement
+        native_unit_of_measurement = self.__native_unit_of_measurement_compat
         unit_of_measurement = self.unit_of_measurement
         value = self.native_value
         # For the sake of validation, we can ignore custom device classes
@@ -765,7 +777,8 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             return display_precision
 
         default_unit_of_measurement = (
-            self.suggested_unit_of_measurement or self.native_unit_of_measurement
+            self.suggested_unit_of_measurement
+            or self.__native_unit_of_measurement_compat
         )
         if default_unit_of_measurement is None:
             return display_precision
@@ -843,7 +856,7 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
             (sensor_options := self.registry_entry.options.get(primary_key))
             and secondary_key in sensor_options
             and (device_class := self.device_class) in UNIT_CONVERTERS
-            and self.native_unit_of_measurement
+            and self.__native_unit_of_measurement_compat
             in UNIT_CONVERTERS[device_class].VALID_UNITS
             and (custom_unit := sensor_options[secondary_key])
             in UNIT_CONVERTERS[device_class].VALID_UNITS

homeassistant/components/sensor/const.py

@@ -9,6 +9,7 @@ import voluptuous as vol
 
 from homeassistant.const import (
     CONCENTRATION_GRAMS_PER_CUBIC_METER,
+    CONCENTRATION_MICROGRAMS_PER_CUBIC_FOOT,
     CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
     CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER,
     CONCENTRATION_PARTS_PER_BILLION,
@@ -167,7 +168,7 @@ class SensorDeviceClass(StrEnum):
     CONDUCTIVITY = "conductivity"
     """Conductivity.
 
-    Unit of measurement: `S/cm`, `mS/cm`, `µS/cm`
+    Unit of measurement: `S/cm`, `mS/cm`, `μS/cm`
     """
 
     CURRENT = "current"
@@ -199,7 +200,7 @@ class SensorDeviceClass(StrEnum):
     DURATION = "duration"
     """Fixed duration.
 
-    Unit of measurement: `d`, `h`, `min`, `s`, `ms`, `µs`
+    Unit of measurement: `d`, `h`, `min`, `s`, `ms`, `μs`
     """
 
     ENERGY = "energy"
@@ -279,25 +280,25 @@ class SensorDeviceClass(StrEnum):
     NITROGEN_DIOXIDE = "nitrogen_dioxide"
     """Amount of NO2.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     NITROGEN_MONOXIDE = "nitrogen_monoxide"
     """Amount of NO.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     NITROUS_OXIDE = "nitrous_oxide"
     """Amount of N2O.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     OZONE = "ozone"
     """Amount of O3.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PH = "ph"
@@ -309,19 +310,19 @@ class SensorDeviceClass(StrEnum):
     PM1 = "pm1"
     """Particulate matter <= 1 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PM10 = "pm10"
     """Particulate matter <= 10 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     PM25 = "pm25"
     """Particulate matter <= 2.5 μm.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     POWER_FACTOR = "power_factor"
@@ -399,7 +400,7 @@ class SensorDeviceClass(StrEnum):
     SULPHUR_DIOXIDE = "sulphur_dioxide"
     """Amount of SO2.
 
-    Unit of measurement: `µg/m³`
+    Unit of measurement: `μg/m³`
     """
 
     TEMPERATURE = "temperature"
@@ -411,7 +412,7 @@ class SensorDeviceClass(StrEnum):
     VOLATILE_ORGANIC_COMPOUNDS = "volatile_organic_compounds"
     """Amount of VOC.
 
-    Unit of measurement: `µg/m³`, `mg/m³`
+    Unit of measurement: `μg/m³`, `mg/m³`
     """
 
     VOLATILE_ORGANIC_COMPOUNDS_PARTS = "volatile_organic_compounds_parts"
@@ -423,7 +424,7 @@ class SensorDeviceClass(StrEnum):
     VOLTAGE = "voltage"
     """Voltage.
 
-    Unit of measurement: `V`, `mV`, `µV`, `kV`, `MV`
+    Unit of measurement: `V`, `mV`, `μV`, `kV`, `MV`
     """
 
     VOLUME = "volume"
@@ -470,7 +471,7 @@ class SensorDeviceClass(StrEnum):
     Weight is used instead of mass to fit with every day language.
 
     Unit of measurement: `MASS_*` units
-    - SI / metric: `µg`, `mg`, `g`, `kg`
+    - SI / metric: `μg`, `mg`, `g`, `kg`
     - USCS / imperial: `oz`, `lb`
     """
 
@@ -788,3 +789,16 @@ DEVICE_CLASS_STATE_CLASSES: dict[SensorDeviceClass, set[SensorStateClass]] = {
 STATE_CLASS_UNITS: dict[SensorStateClass | str, set[type[StrEnum] | str | None]] = {
     SensorStateClass.MEASUREMENT_ANGLE: {DEGREE},
 }
+
+# We translate units that were using using the legacy coding of μ \u00b5
+# to units using recommended coding of μ \u03bc
+AMBIGUOUS_UNITS: dict[str | None, str] = {
+    "\u00b5Sv/h": "μSv/h",  # aranet: radiation rate
+    "\u00b5S/cm": UnitOfConductivity.MICROSIEMENS_PER_CM,
+    "\u00b5V": UnitOfElectricPotential.MICROVOLT,
+    "\u00b5g/ft³": CONCENTRATION_MICROGRAMS_PER_CUBIC_FOOT,
+    "\u00b5g/m³": CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
+    "\u00b5mol/s⋅m²": "μmol/s⋅m²",  # fyta: light
+    "\u00b5g": UnitOfMass.MICROGRAMS,
+    "\u00b5s": UnitOfTime.MICROSECONDS,
+}

homeassistant/components/sensor/recorder.py

@@ -45,6 +45,7 @@ from homeassistant.util.enum import try_parse_enum
 from homeassistant.util.hass_dict import HassKey
 
 from .const import (
+    AMBIGUOUS_UNITS,
     ATTR_LAST_RESET,
     ATTR_STATE_CLASS,
     DOMAIN,
@@ -79,7 +80,7 @@ EQUIVALENT_UNITS = {
     "ft3": UnitOfVolume.CUBIC_FEET,
     "m3": UnitOfVolume.CUBIC_METERS,
     "ft³/m": UnitOfVolumeFlowRate.CUBIC_FEET_PER_MINUTE,
-}
+} | AMBIGUOUS_UNITS
 
 
 # Keep track of entities for which a warning about decreasing value has been logged

homeassistant/components/tomorrowio/sensor.py

@@ -197,7 +197,7 @@ SENSOR_TYPES = (
         attribute=TMRW_ATTR_PRECIPITATION_TYPE,
         value_map=PrecipitationType,
     ),
-    # Data comes in as ppb, convert to µg/m^3
+    # Data comes in as ppb, convert to μg/m^3
     # Molecular weight of Ozone is 48
     TomorrowioSensorEntityDescription(
         key="ozone",
@@ -221,7 +221,7 @@ SENSOR_TYPES = (
         device_class=SensorDeviceClass.PM10,
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    # Data comes in as ppb, convert to µg/m^3
+    # Data comes in as ppb, convert to μg/m^3
     # Molecular weight of Nitrogen Dioxide is 46.01
     TomorrowioSensorEntityDescription(
         key="nitrogen_dioxide",
@@ -240,7 +240,7 @@ SENSOR_TYPES = (
         device_class=SensorDeviceClass.CO,
         state_class=SensorStateClass.MEASUREMENT,
     ),
-    # Data comes in as ppb, convert to µg/m^3
+    # Data comes in as ppb, convert to μg/m^3
     # Molecular weight of Sulphur Dioxide is 64.07
     TomorrowioSensorEntityDescription(
         key="sulphur_dioxide",

homeassistant/components/tuya/const.py

@@ -541,7 +541,9 @@ UNITS = (
     ),
     UnitOfMeasurement(
         unit=CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
-        aliases={"ug/m3", "µg/m3", "ug/m³"},
+        # The μ-char has 2 unicode variants \u00b5 and \u03bc
+        # The \u03bc variant (Greek Mu char) is recommended
+        aliases={"ug/m3", "\u03bcg/m3", "\u00b5g/m3", "ug/m³"},
         device_classes={
             SensorDeviceClass.NITROGEN_DIOXIDE,
             SensorDeviceClass.NITROGEN_MONOXIDE,

homeassistant/const.py

@@ -671,7 +671,7 @@ class UnitOfElectricCurrent(StrEnum):
 class UnitOfElectricPotential(StrEnum):
     """Electric potential units."""
 
-    MICROVOLT = "µV"
+    MICROVOLT = "μV"
     MILLIVOLT = "mV"
     VOLT = "V"
     KILOVOLT = "kV"
@@ -821,7 +821,7 @@ class UnitOfMass(StrEnum):
     GRAMS = "g"
     KILOGRAMS = "kg"
     MILLIGRAMS = "mg"
-    MICROGRAMS = "µg"
+    MICROGRAMS = "μg"
     OUNCES = "oz"
     POUNDS = "lb"
     STONES = "st"
@@ -839,13 +839,13 @@ class UnitOfConductivity(
     """Conductivity units."""
 
     SIEMENS_PER_CM = "S/cm"
-    MICROSIEMENS_PER_CM = "µS/cm"
+    MICROSIEMENS_PER_CM = "μS/cm"
     MILLISIEMENS_PER_CM = "mS/cm"
 
     # Deprecated aliases
     SIEMENS = "S/cm"
     """Deprecated: Please use UnitOfConductivity.SIEMENS_PER_CM"""
-    MICROSIEMENS = "µS/cm"
+    MICROSIEMENS = "μS/cm"
     """Deprecated: Please use UnitOfConductivity.MICROSIEMENS_PER_CM"""
     MILLISIEMENS = "mS/cm"
     """Deprecated: Please use UnitOfConductivity.MILLISIEMENS_PER_CM"""
@@ -917,8 +917,8 @@ class UnitOfPrecipitationDepth(StrEnum):
 
 # Concentration units
 CONCENTRATION_GRAMS_PER_CUBIC_METER: Final = "g/m³"
-CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "µg/m³"
 CONCENTRATION_MILLIGRAMS_PER_CUBIC_METER: Final = "mg/m³"
+CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "μg/m³"
 CONCENTRATION_MICROGRAMS_PER_CUBIC_FOOT: Final = "μg/ft³"
 CONCENTRATION_PARTS_PER_CUBIC_METER: Final = "p/m³"
 CONCENTRATION_PARTS_PER_MILLION: Final = "ppm"

pylint/plugins/hass_enforce_greek_micro_char.py

@@ -0,0 +1,76 @@
+"""Plugin for checking preferred coding of μ is used."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from astroid import nodes
+from pylint.checkers import BaseChecker
+from pylint.lint import PyLinter
+
+
+class HassEnforceGreekMicroCharChecker(BaseChecker):
+    """Checker for micro char."""
+
+    name = "hass-enforce-greek-micro-char"
+    priority = -1
+    msgs = {
+        "W7452": (
+            "Constants with a micro unit prefix must encode the "
+            "small Greek Letter Mu as U+03BC (\u03bc), not as U+00B5 (\u00b5)",
+            "hass-enforce-greek-micro-char",
+            "According to [The Unicode Consortium]"
+            "(https://en.wikipedia.org/wiki/Micro-#Symbol_encoding_in_character_sets),"
+            " the Greek letter character is preferred. "
+            "To search a specific encoded μ char in Microsoft Visual Studio Code, "
+            'make sure the "Match case" option is enabled. Note that this only works '
+            "when searching globally, and not while searching a single document.",
+        ),
+    }
+    options = ()
+
+    def visit_annassign(self, node: nodes.AnnAssign) -> None:
+        """Check for micro char const or StrEnum with type annotations."""
+        self._do_micro_check(node.target, node)
+
+    def visit_assign(self, node: nodes.Assign) -> None:
+        """Check for micro char const without type annotations."""
+        for target in node.targets:
+            self._do_micro_check(target, node)
+
+    def _do_micro_check(
+        self, target: nodes.NodeNG, node: nodes.Assign | nodes.AnnAssign
+    ) -> None:
+        """Check const assignment is not containing ANSI micro char."""
+
+        def _check_const(node_const: nodes.Const | Any) -> bool:
+            if (
+                isinstance(node_const, nodes.Const)
+                and isinstance(node_const.value, str)
+                and "\u00b5" in node_const.value
+            ):
+                self.add_message(self.name, node=node)
+                return True
+            return False
+
+        # Check constant assignments
+        if (
+            isinstance(target, nodes.AssignName)
+            and isinstance(node.value, nodes.Const)
+            and _check_const(node.value)
+        ):
+            return
+
+        # Check dict with EntityDescription calls
+        if isinstance(target, nodes.AssignName) and isinstance(node.value, nodes.Dict):
+            for _, subnode in node.value.items:
+                if not isinstance(subnode, nodes.Call):
+                    continue
+                for keyword in subnode.keywords:
+                    if _check_const(keyword.value):
+                        return
+
+
+def register(linter: PyLinter) -> None:
+    """Register the checker."""
+    linter.register_checker(HassEnforceGreekMicroCharChecker(linter))

pyproject.toml

@@ -121,6 +121,7 @@ load-plugins = [
   "hass_async_load_fixtures",
   "hass_decorator",
   "hass_enforce_class_module",
+  "hass_enforce_greek_micro_char",
   "hass_enforce_sorted_platforms",
   "hass_enforce_super_call",
   "hass_enforce_type_hints",

tests/components/airgradient/snapshots/test_sensor.ambr

@@ -622,7 +622,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '84fce612f5b8-pm01',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[indoor][sensor.airgradient_pm1-state]
@@ -631,7 +631,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Airgradient PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airgradient_pm1',
@@ -675,7 +675,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '84fce612f5b8-pm10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[indoor][sensor.airgradient_pm10-state]
@@ -684,7 +684,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Airgradient PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airgradient_pm10',
@@ -728,7 +728,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '84fce612f5b8-pm02',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[indoor][sensor.airgradient_pm2_5-state]
@@ -737,7 +737,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Airgradient PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airgradient_pm2_5',
@@ -833,7 +833,7 @@
     'supported_features': 0,
     'translation_key': 'raw_pm02',
     'unique_id': '84fce612f5b8-pm02_raw',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[indoor][sensor.airgradient_raw_pm2_5-state]
@@ -842,7 +842,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Airgradient Raw PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airgradient_raw_pm2_5',

tests/components/airly/snapshots/test_sensor.ambr

@@ -36,7 +36,7 @@
     'supported_features': 0,
     'translation_key': 'co',
     'unique_id': '123-456-co',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_carbon_monoxide-state]
@@ -47,7 +47,7 @@
       'limit': 4000,
       'percent': 4,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_carbon_monoxide',
@@ -207,7 +207,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-no2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_nitrogen_dioxide-state]
@@ -219,7 +219,7 @@
       'limit': 25,
       'percent': 64,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_nitrogen_dioxide',
@@ -266,7 +266,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-o3',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_ozone-state]
@@ -278,7 +278,7 @@
       'limit': 100,
       'percent': 42,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_ozone',
@@ -325,7 +325,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-pm1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_pm1-state]
@@ -335,7 +335,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Home PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_pm1',
@@ -382,7 +382,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-pm10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_pm10-state]
@@ -394,7 +394,7 @@
       'limit': 45,
       'percent': 14,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_pm10',
@@ -441,7 +441,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-pm25',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_pm2_5-state]
@@ -453,7 +453,7 @@
       'limit': 15,
       'percent': 29,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_pm2_5',
@@ -557,7 +557,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-456-so2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_sulphur_dioxide-state]
@@ -569,7 +569,7 @@
       'limit': 40,
       'percent': 35,
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_sulphur_dioxide',

tests/components/airthings/snapshots/test_sensor.ambr

@@ -263,7 +263,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '2960000001_pm1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_device_types[view_plus][sensor.living_room_pm1-state]
@@ -272,7 +272,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Living Room PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.living_room_pm1',
@@ -319,7 +319,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '2960000001_pm25',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_device_types[view_plus][sensor.living_room_pm2_5-state]
@@ -328,7 +328,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Living Room PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.living_room_pm2_5',

tests/components/altruist/snapshots/test_sensor.ambr

@@ -319,7 +319,7 @@
     'supported_features': 0,
     'translation_key': 'pm_10',
     'unique_id': '5366960e8b18-SDS_P1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[sensor.5366960e8b18_pm10-state]
@@ -328,7 +328,7 @@
       'device_class': 'pm10',
       'friendly_name': '5366960e8b18 PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.5366960e8b18_pm10',
@@ -375,7 +375,7 @@
     'supported_features': 0,
     'translation_key': 'pm_25',
     'unique_id': '5366960e8b18-SDS_P2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[sensor.5366960e8b18_pm2_5-state]
@@ -384,7 +384,7 @@
       'device_class': 'pm25',
       'friendly_name': '5366960e8b18 PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.5366960e8b18_pm2_5',

tests/components/arve/snapshots/test_sensor.ambr

@@ -144,7 +144,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'test-serial-number_PM10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[entry_pm2_5]
@@ -181,7 +181,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'test-serial-number_PM25',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[entry_temperature]
@@ -314,7 +314,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Test Sensor PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.test_sensor_pm10',
@@ -330,7 +330,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Test Sensor PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.test_sensor_pm2_5',

tests/components/bthome/test_sensor.py

@@ -253,14 +253,14 @@ _LOGGER = logging.getLogger(__name__)
                 {
                     "sensor_entity": "sensor.test_device_18b2_pm10",
                     "friendly_name": "Test Device 18B2 Pm10",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "7170",
                 },
                 {
                     "sensor_entity": "sensor.test_device_18b2_pm25",
                     "friendly_name": "Test Device 18B2 Pm25",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "3090",
                 },
@@ -296,7 +296,7 @@ _LOGGER = logging.getLogger(__name__)
                         "sensor.test_device_18b2_volatile_organic_compounds"
                     ),
                     "friendly_name": "Test Device 18B2 Volatile Organic Compounds",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "307",
                 },
@@ -607,14 +607,14 @@ async def test_v1_sensors(
                 {
                     "sensor_entity": "sensor.test_device_18b2_pm10",
                     "friendly_name": "Test Device 18B2 Pm10",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "7170",
                 },
                 {
                     "sensor_entity": "sensor.test_device_18b2_pm25",
                     "friendly_name": "Test Device 18B2 Pm25",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "3090",
                 },
@@ -650,7 +650,7 @@ async def test_v1_sensors(
                         "sensor.test_device_18b2_volatile_organic_compounds"
                     ),
                     "friendly_name": "Test Device 18B2 Volatile Organic Compounds",
-                    "unit_of_measurement": "µg/m³",
+                    "unit_of_measurement": "μg/m³",
                     "state_class": "measurement",
                     "expected_state": "307",
                 },

tests/components/deconz/snapshots/test_sensor.ambr

@@ -829,7 +829,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'xx:xx:xx:xx:xx:xx:xx:xx-01-042a-particulate_matter_pm2_5',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload14-expected14][sensor.starkvind_airpurifier_pm25-state]
@@ -838,7 +838,7 @@
       'device_class': 'pm25',
       'friendly_name': 'STARKVIND AirPurifier PM25',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.starkvind_airpurifier_pm25',
@@ -1377,7 +1377,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_formaldehyde',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload2-expected2][sensor.airquality_1_ch2o-state]
@@ -1386,7 +1386,7 @@
       'device_class': 'volatile_organic_compounds',
       'friendly_name': 'AirQuality 1 CH2O',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_ch2o',
@@ -1483,7 +1483,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_pm2_5',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload2-expected2][sensor.airquality_1_pm25-state]
@@ -1492,7 +1492,7 @@
       'device_class': 'pm25',
       'friendly_name': 'AirQuality 1 PM25',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_pm25',
@@ -1699,7 +1699,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_formaldehyde',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload3-expected3][sensor.airquality_1_ch2o-state]
@@ -1708,7 +1708,7 @@
       'device_class': 'volatile_organic_compounds',
       'friendly_name': 'AirQuality 1 CH2O',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_ch2o',
@@ -1805,7 +1805,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_pm2_5',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload3-expected3][sensor.airquality_1_pm25-state]
@@ -1814,7 +1814,7 @@
       'device_class': 'pm25',
       'friendly_name': 'AirQuality 1 PM25',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_pm25',
@@ -1910,7 +1910,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_formaldehyde',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload4-expected4][sensor.airquality_1_ch2o-state]
@@ -1919,7 +1919,7 @@
       'device_class': 'volatile_organic_compounds',
       'friendly_name': 'AirQuality 1 CH2O',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_ch2o',
@@ -2016,7 +2016,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00:00:00:00:00:00:00:01-02-0113-air_quality_pm2_5',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[config_entry_options0-sensor_payload4-expected4][sensor.airquality_1_pm25-state]
@@ -2025,7 +2025,7 @@
       'device_class': 'pm25',
       'friendly_name': 'AirQuality 1 PM25',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.airquality_1_pm25',

tests/components/derivative/test_config_flow.py

@@ -68,8 +68,14 @@ async def test_config_flow(hass: HomeAssistant, platform) -> None:
 
 
 @pytest.mark.parametrize("platform", ["sensor"])
-async def test_options(hass: HomeAssistant, platform) -> None:
+@pytest.mark.parametrize(
-    """Test reconfiguring."""
+    ("unit_prefix_entry", "unit_prefix_used"),
+    [("k", "k"), ("\u00b5", "\u03bc"), ("\u03bc", "\u03bc")],
+)
+async def test_options(
+    hass: HomeAssistant, platform, unit_prefix_entry: str, unit_prefix_used: str
+) -> None:
+    """Test reconfiguring and migrated unit prefix."""
     # Setup the config entry
     config_entry = MockConfigEntry(
         data={},
@@ -79,7 +85,7 @@ async def test_options(hass: HomeAssistant, platform) -> None:
             "round": 1.0,
             "source": "sensor.input",
             "time_window": {"seconds": 0.0},
-            "unit_prefix": "k",
+            "unit_prefix": unit_prefix_entry,
             "unit_time": "min",
             "max_sub_interval": {"seconds": 30},
         },
@@ -99,7 +105,7 @@ async def test_options(hass: HomeAssistant, platform) -> None:
     schema = result["data_schema"].schema
     assert get_schema_suggested_value(schema, "round") == 1.0
     assert get_schema_suggested_value(schema, "time_window") == {"seconds": 0.0}
-    assert get_schema_suggested_value(schema, "unit_prefix") == "k"
+    assert get_schema_suggested_value(schema, "unit_prefix") == unit_prefix_used
     assert get_schema_suggested_value(schema, "unit_time") == "min"
 
     source = schema["source"]

tests/components/derivative/test_init.py

@@ -519,7 +519,7 @@ async def test_migration_1_1(hass: HomeAssistant, unit_prefix, expect_prefix) ->
     assert config_entry.options.get("unit_prefix") == expect_prefix
 
     assert config_entry.version == 1
-    assert config_entry.minor_version == 3
+    assert config_entry.minor_version == 4
 
 
 async def test_migration_1_2(
@@ -570,7 +570,44 @@ async def test_migration_1_2(
     assert derivative_entity_entry.device_id == sensor_entity_entry.device_id
 
     assert derivative_config_entry.version == 1
-    assert derivative_config_entry.minor_version == 3
+    assert derivative_config_entry.minor_version == 4
+
+
+@pytest.mark.parametrize(
+    ("unit_prefix", "expect_prefix"),
+    [
+        ({"unit_prefix": "\u00b5"}, "\u03bc"),
+        ({"unit_prefix": "\u03bc"}, "\u03bc"),
+    ],
+)
+async def test_migration_1_4(hass: HomeAssistant, unit_prefix, expect_prefix) -> None:
+    """Test migration from v1.4 migrates to Greek Mu char" unit_prefix."""
+
+    config_entry = MockConfigEntry(
+        data={},
+        domain=DOMAIN,
+        options={
+            "name": "My derivative",
+            "round": 1.0,
+            "source": "sensor.power",
+            "time_window": {"seconds": 0.0},
+            **unit_prefix,
+            "unit_time": "min",
+        },
+        title="My derivative",
+        version=1,
+        minor_version=1,
+    )
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.LOADED
+    assert config_entry.options["unit_time"] == "min"
+    assert config_entry.options.get("unit_prefix") == expect_prefix
+
+    assert config_entry.version == 1
+    assert config_entry.minor_version == 4
 
 
 async def test_migration_from_future_version(

tests/components/gios/snapshots/test_sensor.ambr

@@ -103,7 +103,7 @@
     'supported_features': 0,
     'translation_key': 'c6h6',
     'unique_id': '123-c6h6',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_benzene-state]
@@ -112,7 +112,7 @@
       'attribution': 'Data provided by GIOŚ',
       'friendly_name': 'Home Benzene',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_benzene',
@@ -159,7 +159,7 @@
     'supported_features': 0,
     'translation_key': 'co',
     'unique_id': '123-co',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_carbon_monoxide-state]
@@ -168,7 +168,7 @@
       'attribution': 'Data provided by GIOŚ',
       'friendly_name': 'Home Carbon monoxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_carbon_monoxide',
@@ -215,7 +215,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-no2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_nitrogen_dioxide-state]
@@ -225,7 +225,7 @@
       'device_class': 'nitrogen_dioxide',
       'friendly_name': 'Home Nitrogen dioxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_nitrogen_dioxide',
@@ -339,7 +339,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-no',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_nitrogen_monoxide-state]
@@ -349,7 +349,7 @@
       'device_class': 'nitrogen_monoxide',
       'friendly_name': 'Home Nitrogen monoxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_nitrogen_monoxide',
@@ -396,7 +396,7 @@
     'supported_features': 0,
     'translation_key': 'nox',
     'unique_id': '123-nox',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_nitrogen_oxides-state]
@@ -405,7 +405,7 @@
       'attribution': 'Data provided by GIOŚ',
       'friendly_name': 'Home Nitrogen oxides',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_nitrogen_oxides',
@@ -452,7 +452,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-o3',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_ozone-state]
@@ -462,7 +462,7 @@
       'device_class': 'ozone',
       'friendly_name': 'Home Ozone',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_ozone',
@@ -576,7 +576,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-pm10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_pm10-state]
@@ -586,7 +586,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Home PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_pm10',
@@ -700,7 +700,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-pm25',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_pm2_5-state]
@@ -710,7 +710,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Home PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_pm2_5',
@@ -824,7 +824,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '123-so2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.home_sulphur_dioxide-state]
@@ -834,7 +834,7 @@
       'device_class': 'sulphur_dioxide',
       'friendly_name': 'Home Sulphur dioxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.home_sulphur_dioxide',

tests/components/govee_ble/test_sensor.py

@@ -183,7 +183,7 @@ async def test_gvh5106(hass: HomeAssistant) -> None:
     pm25_sensor_attributes = pm25_sensor.attributes
     assert pm25_sensor.state == "0"
     assert pm25_sensor_attributes[ATTR_FRIENDLY_NAME] == "H5106 4E05 Pm25"
-    assert pm25_sensor_attributes[ATTR_UNIT_OF_MEASUREMENT] == "µg/m³"
+    assert pm25_sensor_attributes[ATTR_UNIT_OF_MEASUREMENT] == "μg/m³"
     assert pm25_sensor_attributes[ATTR_STATE_CLASS] == "measurement"
 
     assert await hass.config_entries.async_unload(entry.entry_id)

tests/components/homekit_controller/snapshots/test_init.ambr

@@ -363,14 +363,14 @@
             'supported_features': 0,
             'translation_key': None,
             'unique_id': '00:00:00:00:00:00_1_2576_2580',
-            'unit_of_measurement': 'µg/m³',
+            'unit_of_measurement': 'μg/m³',
           }),
           'state': dict({
             'attributes': dict({
               'device_class': 'pm25',
               'friendly_name': 'Airversa AP2 1808 PM2.5 Density',
               'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-              'unit_of_measurement': 'µg/m³',
+              'unit_of_measurement': 'μg/m³',
             }),
             'entity_id': 'sensor.airversa_ap2_1808_pm2_5_density',
             'state': '3.0',

tests/components/iron_os/snapshots/test_number.ambr

@@ -94,7 +94,7 @@
     'supported_features': 0,
     'translation_key': <PinecilNumber.CALIBRATION_OFFSET: 'calibration_offset'>,
     'unique_id': 'c0:ff:ee:c0:ff:ee_calibration_offset',
-    'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'µV'>,
+    'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'μV'>,
   })
 # ---
 # name: test_state[number.pinecil_calibration_offset-state]
@@ -105,7 +105,7 @@
       'min': 100,
       'mode': <NumberMode.BOX: 'box'>,
       'step': 1,
-      'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'µV'>,
+      'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'μV'>,
     }),
     'context': <ANY>,
     'entity_id': 'number.pinecil_calibration_offset',

tests/components/iron_os/snapshots/test_sensor.ambr

@@ -566,7 +566,7 @@
     'supported_features': 0,
     'translation_key': <PinecilSensor.TIP_VOLTAGE: 'tip_voltage'>,
     'unique_id': 'c0:ff:ee:c0:ff:ee_tip_voltage',
-    'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'µV'>,
+    'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'μV'>,
   })
 # ---
 # name: test_sensors[sensor.pinecil_raw_tip_voltage-state]
@@ -575,7 +575,7 @@
       'device_class': 'voltage',
       'friendly_name': 'Pinecil Raw tip voltage',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'µV'>,
+      'unit_of_measurement': <UnitOfElectricPotential.MICROVOLT: 'μV'>,
     }),
     'context': <ANY>,
     'entity_id': 'sensor.pinecil_raw_tip_voltage',

tests/components/lg_thinq/snapshots/test_sensor.ambr

@@ -135,7 +135,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'MW2-2E247F93-B570-46A6-B827-920E9E10F966_pm1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[sensor.test_air_conditioner_pm1-state]
@@ -144,7 +144,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Test air conditioner PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.test_air_conditioner_pm1',
@@ -188,7 +188,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'MW2-2E247F93-B570-46A6-B827-920E9E10F966_pm10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[sensor.test_air_conditioner_pm10-state]
@@ -197,7 +197,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Test air conditioner PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.test_air_conditioner_pm10',
@@ -241,7 +241,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'MW2-2E247F93-B570-46A6-B827-920E9E10F966_pm2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[sensor.test_air_conditioner_pm2_5-state]
@@ -250,7 +250,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Test air conditioner PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.test_air_conditioner_pm2_5',

tests/components/matter/snapshots/test_sensor.ambr

@@ -468,7 +468,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-000000000000008F-MatterNodeDevice-2-PM1Sensor-1068-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_purifier][sensor.air_purifier_pm1-state]
@@ -477,7 +477,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Air Purifier PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.air_purifier_pm1',
@@ -521,7 +521,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-000000000000008F-MatterNodeDevice-2-PM10Sensor-1069-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_purifier][sensor.air_purifier_pm10-state]
@@ -530,7 +530,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Air Purifier PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.air_purifier_pm10',
@@ -574,7 +574,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-000000000000008F-MatterNodeDevice-2-PM25Sensor-1066-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_purifier][sensor.air_purifier_pm2_5-state]
@@ -583,7 +583,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Air Purifier PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.air_purifier_pm2_5',
@@ -1017,7 +1017,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-0000000000000001-MatterNodeDevice-1-PM1Sensor-1068-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_quality_sensor][sensor.lightfi_aq1_air_quality_sensor_pm1-state]
@@ -1026,7 +1026,7 @@
       'device_class': 'pm1',
       'friendly_name': 'lightfi-aq1-air-quality-sensor PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.lightfi_aq1_air_quality_sensor_pm1',
@@ -1070,7 +1070,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-0000000000000001-MatterNodeDevice-1-PM10Sensor-1069-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_quality_sensor][sensor.lightfi_aq1_air_quality_sensor_pm10-state]
@@ -1079,7 +1079,7 @@
       'device_class': 'pm10',
       'friendly_name': 'lightfi-aq1-air-quality-sensor PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.lightfi_aq1_air_quality_sensor_pm10',
@@ -1123,7 +1123,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '00000000000004D2-0000000000000001-MatterNodeDevice-1-PM25Sensor-1066-0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[air_quality_sensor][sensor.lightfi_aq1_air_quality_sensor_pm2_5-state]
@@ -1132,7 +1132,7 @@
       'device_class': 'pm25',
       'friendly_name': 'lightfi-aq1-air-quality-sensor PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.lightfi_aq1_air_quality_sensor_pm2_5',

tests/components/mqtt/test_number.py

@@ -26,6 +26,7 @@ from homeassistant.const import (
     ATTR_ENTITY_ID,
     ATTR_MODE,
     ATTR_UNIT_OF_MEASUREMENT,
+    UnitOfElectricPotential,
     UnitOfTemperature,
 )
 from homeassistant.core import HomeAssistant, State
@@ -253,6 +254,62 @@ async def test_native_value_validation(
     mqtt_mock.async_publish.reset_mock()
 
 
+@pytest.mark.parametrize(
+    "hass_config",
+    [
+        {
+            mqtt.DOMAIN: {
+                number.DOMAIN: {
+                    "name": "test",
+                    "command_topic": "test-topic-cmd",
+                    "state_topic": "test-topic",
+                    "unit_of_measurement": "\u00b5V",
+                }
+            }
+        }
+    ],
+)
+async def test_equivalent_unit_of_measurement(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test device_class with equivalent unit of measurement."""
+    assert await mqtt_mock_entry()
+    async_fire_mqtt_message(hass, "test-topic", "100")
+    await hass.async_block_till_done()
+    state = hass.states.get("number.test")
+    assert state is not None
+    assert state.state == "100"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+    caplog.clear()
+
+    discovery_payload = {
+        "name": "bla",
+        "command_topic": "test-topic2-cmd",
+        "state_topic": "test-topic2",
+        "unit_of_measurement": "\u00b5V",
+    }
+    # Now discover an invalid sensor
+    async_fire_mqtt_message(
+        hass, "homeassistant/number/bla/config", json.dumps(discovery_payload)
+    )
+    await hass.async_block_till_done()
+    async_fire_mqtt_message(hass, "test-topic2", "21")
+    await hass.async_block_till_done()
+    state = hass.states.get("number.bla")
+    assert state is not None
+    assert state.state == "21"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+
 @pytest.mark.parametrize(
     "hass_config",
     [

tests/components/mqtt/test_sensor.py

@@ -15,9 +15,11 @@ import pytest
 from homeassistant.components import mqtt, sensor
 from homeassistant.components.mqtt.sensor import MQTT_SENSOR_ATTRIBUTES_BLOCKED
 from homeassistant.const import (
+    ATTR_UNIT_OF_MEASUREMENT,
     EVENT_STATE_CHANGED,
     STATE_UNAVAILABLE,
     STATE_UNKNOWN,
+    UnitOfElectricPotential,
     UnitOfTemperature,
 )
 from homeassistant.core import Event, HomeAssistant, State, callback
@@ -906,6 +908,116 @@ async def test_invalid_unit_of_measurement(
     assert state is None
 
 
+@pytest.mark.parametrize(
+    "hass_config",
+    [
+        {
+            mqtt.DOMAIN: {
+                sensor.DOMAIN: {
+                    "name": "test",
+                    "state_topic": "test-topic",
+                    "device_class": "voltage",
+                    "unit_of_measurement": "\u00b5V",  # microVolt
+                }
+            }
+        }
+    ],
+)
+async def test_device_class_with_equivalent_unit_of_measurement_received(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test device_class with equivalent unit of measurement."""
+    assert await mqtt_mock_entry()
+    async_fire_mqtt_message(hass, "test-topic", "100")
+    await hass.async_block_till_done()
+    state = hass.states.get("sensor.test")
+    assert state is not None
+    assert state.state == "100"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+    caplog.clear()
+
+    discovery_payload = {
+        "name": "bla",
+        "state_topic": "test-topic2",
+        "device_class": "voltage",
+        "unit_of_measurement": "\u00b5V",
+    }
+    # Now discover a sensor with an altarantive mu char
+    async_fire_mqtt_message(
+        hass, "homeassistant/sensor/bla/config", json.dumps(discovery_payload)
+    )
+    await hass.async_block_till_done()
+    async_fire_mqtt_message(hass, "test-topic2", "21")
+    await hass.async_block_till_done()
+    state = hass.states.get("sensor.bla")
+    assert state is not None
+    assert state.state == "21"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+
+@pytest.mark.parametrize(
+    "hass_config",
+    [
+        {
+            mqtt.DOMAIN: {
+                sensor.DOMAIN: {
+                    "name": "test",
+                    "state_topic": "test-topic",
+                    "unit_of_measurement": "\u00b5V",
+                }
+            }
+        }
+    ],
+)
+async def test_equivalent_unit_of_measurement_received_without_device_class(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test device_class with equivalent unit of measurement."""
+    assert await mqtt_mock_entry()
+    async_fire_mqtt_message(hass, "test-topic", "100")
+    await hass.async_block_till_done()
+    state = hass.states.get("sensor.test")
+    assert state is not None
+    assert state.state == "100"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+    caplog.clear()
+
+    discovery_payload = {
+        "name": "bla",
+        "state_topic": "test-topic2",
+        "unit_of_measurement": "\u00b5V",
+    }
+    # Now discover an invalid sensor
+    async_fire_mqtt_message(
+        hass, "homeassistant/sensor/bla/config", json.dumps(discovery_payload)
+    )
+    await hass.async_block_till_done()
+    async_fire_mqtt_message(hass, "test-topic2", "21")
+    await hass.async_block_till_done()
+    state = hass.states.get("sensor.bla")
+    assert state is not None
+    assert state.state == "21"
+    assert (
+        state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+        is UnitOfElectricPotential.MICROVOLT
+    )
+
+
 @pytest.mark.parametrize(
     "hass_config",
     [

tests/components/nam/snapshots/test_sensor.ambr

@@ -981,7 +981,7 @@
     'supported_features': 0,
     'translation_key': 'pmsx003_pm1',
     'unique_id': 'aa:bb:cc:dd:ee:ff-pms_p0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_pmsx003_pm1-state]
@@ -990,7 +990,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Nettigo Air Monitor PMSx003 PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_pmsx003_pm1',
@@ -1037,7 +1037,7 @@
     'supported_features': 0,
     'translation_key': 'pmsx003_pm10',
     'unique_id': 'aa:bb:cc:dd:ee:ff-pms_p1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_pmsx003_pm10-state]
@@ -1046,7 +1046,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Nettigo Air Monitor PMSx003 PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_pmsx003_pm10',
@@ -1093,7 +1093,7 @@
     'supported_features': 0,
     'translation_key': 'pmsx003_pm25',
     'unique_id': 'aa:bb:cc:dd:ee:ff-pms_p2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_pmsx003_pm2_5-state]
@@ -1102,7 +1102,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Nettigo Air Monitor PMSx003 PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_pmsx003_pm2_5',
@@ -1261,7 +1261,7 @@
     'supported_features': 0,
     'translation_key': 'sds011_pm10',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sds011_p1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sds011_pm10-state]
@@ -1270,7 +1270,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Nettigo Air Monitor SDS011 PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sds011_pm10',
@@ -1317,7 +1317,7 @@
     'supported_features': 0,
     'translation_key': 'sds011_pm25',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sds011_p2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sds011_pm2_5-state]
@@ -1326,7 +1326,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Nettigo Air Monitor SDS011 PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sds011_pm2_5',
@@ -1653,7 +1653,7 @@
     'supported_features': 0,
     'translation_key': 'sps30_pm1',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sps30_p0',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sps30_pm1-state]
@@ -1662,7 +1662,7 @@
       'device_class': 'pm1',
       'friendly_name': 'Nettigo Air Monitor SPS30 PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sps30_pm1',
@@ -1709,7 +1709,7 @@
     'supported_features': 0,
     'translation_key': 'sps30_pm10',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sps30_p1',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sps30_pm10-state]
@@ -1718,7 +1718,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Nettigo Air Monitor SPS30 PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sps30_pm10',
@@ -1765,7 +1765,7 @@
     'supported_features': 0,
     'translation_key': 'sps30_pm25',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sps30_p2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sps30_pm2_5-state]
@@ -1774,7 +1774,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Nettigo Air Monitor SPS30 PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sps30_pm2_5',
@@ -1821,7 +1821,7 @@
     'supported_features': 0,
     'translation_key': 'sps30_pm4',
     'unique_id': 'aa:bb:cc:dd:ee:ff-sps30_p4',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor[sensor.nettigo_air_monitor_sps30_pm4-state]
@@ -1829,7 +1829,7 @@
     'attributes': ReadOnlyDict({
       'friendly_name': 'Nettigo Air Monitor SPS30 PM4',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.nettigo_air_monitor_sps30_pm4',

tests/components/number/test_init.py

@@ -7,6 +7,7 @@ from unittest.mock import MagicMock, patch
 import pytest
 
 from homeassistant.components.number import (
+    AMBIGUOUS_UNITS,
     ATTR_MAX,
     ATTR_MIN,
     ATTR_MODE,
@@ -48,6 +49,7 @@ from . import common
 
 from tests.common import (
     MockConfigEntry,
+    MockEntity,
     MockModule,
     MockPlatform,
     async_mock_restore_state_shutdown_restart,
@@ -61,6 +63,25 @@ from tests.common import (
 TEST_DOMAIN = "test"
 
 
+class MockNumber(MockEntity, NumberEntity):
+    """Mock NumberEntity class to test unit of measurement."""
+
+    @property
+    def device_class(self):
+        """Return the class of this sensor."""
+        return self._handle("device_class")
+
+    @property
+    def native_unit_of_measurement(self):
+        """Return the native unit_of_measurement of this sensor."""
+        return self._handle("native_unit_of_measurement")
+
+    @property
+    def native_value(self):
+        """Return the native value of this sensor."""
+        return self._handle("native_value")
+
+
 class MockDefaultNumberEntity(NumberEntity):
     """Mock NumberEntity device to use in tests.
 
@@ -900,6 +921,33 @@ async def test_translated_unit_with_native_unit_raises(
         assert entity0.entity_id is None
 
 
+@pytest.mark.parametrize(
+    ("ambiguous_unit", "normalized_unit"),
+    [
+        (ambiguous_unit, normalized_unit)
+        for ambiguous_unit, normalized_unit in AMBIGUOUS_UNITS.items()
+    ],
+)
+async def test_ambiguous_unit_of_measurement_compat(
+    hass: HomeAssistant, ambiguous_unit: str, normalized_unit: str
+) -> None:
+    """Test ambiguous native_unit_of_measurement values are corrected."""
+    entity0 = MockNumber(
+        name="Test",
+        native_value="0.0",
+        native_unit_of_measurement=ambiguous_unit,
+    )
+    setup_test_component_platform(hass, DOMAIN, [entity0])
+
+    assert await async_setup_component(hass, "number", {"number": {"platform": "test"}})
+    await hass.async_block_till_done()
+
+    # Check compatible unit is applied
+    state = hass.states.get(entity0.entity_id)
+    assert state.state == "0.0"
+    assert state.attributes[ATTR_UNIT_OF_MEASUREMENT] == normalized_unit
+
+
 def test_device_classes_aligned() -> None:
     """Make sure all sensor device classes are also available in NumberDeviceClass."""
 

tests/components/openweathermap/snapshots/test_sensor.ambr

@@ -86,7 +86,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-co',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_carbon_monoxide-state]
@@ -96,7 +96,7 @@
       'device_class': 'carbon_monoxide',
       'friendly_name': 'openweathermap Carbon monoxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_carbon_monoxide',
@@ -140,7 +140,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-no2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_nitrogen_dioxide-state]
@@ -150,7 +150,7 @@
       'device_class': 'nitrogen_dioxide',
       'friendly_name': 'openweathermap Nitrogen dioxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_nitrogen_dioxide',
@@ -194,7 +194,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-no',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_nitrogen_monoxide-state]
@@ -204,7 +204,7 @@
       'device_class': 'nitrogen_monoxide',
       'friendly_name': 'openweathermap Nitrogen monoxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_nitrogen_monoxide',
@@ -248,7 +248,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-o3',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_ozone-state]
@@ -258,7 +258,7 @@
       'device_class': 'ozone',
       'friendly_name': 'openweathermap Ozone',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_ozone',
@@ -302,7 +302,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-pm10',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_pm10-state]
@@ -312,7 +312,7 @@
       'device_class': 'pm10',
       'friendly_name': 'openweathermap PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_pm10',
@@ -356,7 +356,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-pm2_5',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_pm2_5-state]
@@ -366,7 +366,7 @@
       'device_class': 'pm25',
       'friendly_name': 'openweathermap PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_pm2_5',
@@ -410,7 +410,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '12.34-56.78-so2',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensor_states[air_pollution][sensor.openweathermap_sulphur_dioxide-state]
@@ -420,7 +420,7 @@
       'device_class': 'sulphur_dioxide',
       'friendly_name': 'openweathermap Sulphur dioxide',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.openweathermap_sulphur_dioxide',

tests/components/ruuvitag_ble/snapshots/test_sensor.ambr

@@ -776,7 +776,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': '01:03:05:07:12:34-pm25',
-    'unit_of_measurement': <Units.CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: 'µg/m³'>,
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_sensors[v6][sensor.ruuvitag_884f_pm2_5-state]
@@ -785,7 +785,7 @@
       'device_class': 'pm25',
       'friendly_name': 'RuuviTag 884F PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': <Units.CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: 'µg/m³'>,
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.ruuvitag_884f_pm2_5',

tests/components/sensor/test_init.py

@@ -11,8 +11,12 @@ from unittest.mock import patch
 import pytest
 
 from homeassistant.components import sensor
-from homeassistant.components.number import NumberDeviceClass
+from homeassistant.components.number import (
+    AMBIGUOUS_UNITS as NUMBER_AMBIGUOUS_UNITS,
+    NumberDeviceClass,
+)
 from homeassistant.components.sensor import (
+    AMBIGUOUS_UNITS as SENSOR_AMBIGUOUS_UNITS,
     DEVICE_CLASS_STATE_CLASSES,
     DEVICE_CLASS_UNITS,
     DOMAIN,
@@ -159,12 +163,47 @@ async def test_temperature_conversion_wrong_device_class(
     assert await async_setup_component(hass, "sensor", {"sensor": {"platform": "test"}})
     await hass.async_block_till_done()
 
-    # Check temperature is not converted
+    # Check compatible unit is applied
     state = hass.states.get(entity0.entity_id)
     assert state.state == "0.0"
     assert state.attributes[ATTR_UNIT_OF_MEASUREMENT] == UnitOfTemperature.FAHRENHEIT
 
 
+@pytest.mark.parametrize(
+    ("ambiguous_unit", "normalized_unit"),
+    [
+        (ambiguous_unit, normalized_unit)
+        for ambiguous_unit, normalized_unit in sensor.AMBIGUOUS_UNITS.items()
+    ],
+)
+async def test_ambiguous_unit_of_measurement_compat(
+    hass: HomeAssistant, ambiguous_unit: str, normalized_unit: str
+) -> None:
+    """Test ambiguous native_unit_of_measurement values are corrected."""
+    entity0 = MockSensor(
+        name="Test",
+        native_value="0.0",
+        native_unit_of_measurement=ambiguous_unit,
+    )
+    setup_test_component_platform(hass, sensor.DOMAIN, [entity0])
+
+    assert await async_setup_component(hass, "sensor", {"sensor": {"platform": "test"}})
+    await hass.async_block_till_done()
+
+    # Check temperature is not converted
+    state = hass.states.get(entity0.entity_id)
+    assert state.state == "0.0"
+    assert state.attributes[ATTR_UNIT_OF_MEASUREMENT] == normalized_unit
+
+
+def test_ambiguous_units_of_measurement_aligned() -> None:
+    """Make sure all ambiguous UOM for sensor are also available for number."""
+
+    for ambiguous_unit, unit in SENSOR_AMBIGUOUS_UNITS.items():
+        assert ambiguous_unit in NUMBER_AMBIGUOUS_UNITS
+        assert NUMBER_AMBIGUOUS_UNITS[ambiguous_unit] == unit
+
+
 @pytest.mark.parametrize("state_class", ["measurement", "total_increasing"])
 async def test_deprecated_last_reset(
     hass: HomeAssistant,

tests/components/sensor/test_recorder.py

@@ -3755,6 +3755,44 @@ async def test_compile_hourly_statistics_convert_units_1(
             30,
         ),
         (None, "m3", "m³", None, "volume", 13.050847, 13.333333, -10, 30),
+        (None, "\u00b5V", "\u03bcV", None, "voltage", 13.050847, 13.333333, -10, 30),
+        (None, "\u00b5Sv/h", "\u03bcSv/h", None, None, 13.050847, 13.333333, -10, 30),
+        (
+            None,
+            "\u00b5S/cm",
+            "\u03bcS/cm",
+            None,
+            "conductivity",
+            13.050847,
+            13.333333,
+            -10,
+            30,
+        ),
+        (None, "\u00b5g/ft³", "\u03bcg/ft³", None, None, 13.050847, 13.333333, -10, 30),
+        (
+            None,
+            "\u00b5g/m³",
+            "\u03bcg/m³",
+            None,
+            "concentration",
+            13.050847,
+            13.333333,
+            -10,
+            30,
+        ),
+        (
+            None,
+            "\u00b5mol/s⋅m²",
+            "\u03bcmol/s⋅m²",
+            None,
+            None,
+            13.050847,
+            13.333333,
+            -10,
+            30,
+        ),
+        (None, "\u00b5g", "\u03bcg", None, "mass", 13.050847, 13.333333, -10, 30),
+        (None, "\u00b5s", "\u03bcs", None, "duration", 13.050847, 13.333333, -10, 30),
     ],
 )
 async def test_compile_hourly_statistics_equivalent_units_1(
@@ -3884,6 +3922,17 @@ async def test_compile_hourly_statistics_equivalent_units_1(
         (None, "ft3", "ft³", None, 13.333333, -10, 30),
         (None, "ft³/m", "ft³/min", None, 13.333333, -10, 30),
         (None, "m3", "m³", None, 13.333333, -10, 30),
+        (None, "\u00b5V", "\u03bcV", None, 13.333333, -10, 30),
+        (SensorDeviceClass.VOLTAGE, "\u00b5V", "\u03bcV", None, 13.333333, -10, 30),
+        (None, "\u00b5Sv/h", "\u03bcSv/h", None, 13.333333, -10, 30),
+        (None, "\u00b5S/cm", "\u03bcS/cm", None, 13.333333, -10, 30),
+        (None, "\u00b5g/ft³", "\u03bcg/ft³", None, 13.333333, -10, 30),
+        (None, "\u00b5g/m³", "\u03bcg/m³", None, 13.333333, -10, 30),
+        (None, "\u00b5mol/s⋅m²", "\u03bcmol/s⋅m²", None, 13.333333, -10, 30),
+        (None, "\u00b5g", "\u03bcg", None, 13.333333, -10, 30),
+        (SensorDeviceClass.WEIGHT, "\u00b5g", "\u03bcg", None, 13.333333, -10, 30),
+        (None, "\u00b5s", "\u03bcs", None, 13.333333, -10, 30),
+        (SensorDeviceClass.DURATION, "\u00b5s", "\u03bcs", None, 13.333333, -10, 30),
     ],
 )
 async def test_compile_hourly_statistics_equivalent_units_2(
@@ -5705,6 +5754,14 @@ async def test_validate_statistics_unit_change_no_conversion(
         (NONE_SENSOR_ATTRIBUTES, "m3", "m³"),
         (NONE_SENSOR_ATTRIBUTES, "rpm", "RPM"),
         (NONE_SENSOR_ATTRIBUTES, "RPM", "rpm"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5V", "\u03bcV"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5Sv/h", "\u03bcSv/h"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5S/cm", "\u03bcS/cm"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5g/ft³", "\u03bcg/ft³"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5g/m³", "\u03bcg/m³"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5mol/s⋅m²", "\u03bcmol/s⋅m²"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5g", "\u03bcg"),
+        (NONE_SENSOR_ATTRIBUTES, "\u00b5s", "\u03bcs"),
     ],
 )
 async def test_validate_statistics_unit_change_equivalent_units(
@@ -5768,6 +5825,15 @@ async def test_validate_statistics_unit_change_equivalent_units(
     ("attributes", "unit1", "unit2", "supported_unit"),
     [
         (NONE_SENSOR_ATTRIBUTES, "m³", "m3", "CCF, L, fl. oz., ft³, gal, mL, m³"),
+        (NONE_SENSOR_ATTRIBUTES, "\u03bcV", "\u00b5V", "MV, V, kV, mV, \u03bcV"),
+        (NONE_SENSOR_ATTRIBUTES, "\u03bcS/cm", "\u00b5S/cm", "S/cm, mS/cm, \u03bcS/cm"),
+        (
+            NONE_SENSOR_ATTRIBUTES,
+            "\u03bcg",
+            "\u00b5g",
+            "g, kg, lb, mg, oz, st, \u03bcg",
+        ),
+        (NONE_SENSOR_ATTRIBUTES, "\u03bcs", "\u00b5s", "d, h, min, ms, s, w, \u03bcs"),
     ],
 )
 async def test_validate_statistics_unit_change_equivalent_units_2(

tests/components/smartthings/snapshots/test_sensor.ambr

@@ -250,7 +250,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'e44d4e5c-45ea-498f-a653-f5d0c3d97bb8_main_fineDustSensor_fineDustLevel_fineDustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[aq_sensor_3_ikea][sensor.aq_sensor_3_ikea_pm2_5-state]
@@ -259,7 +259,7 @@
       'device_class': 'pm25',
       'friendly_name': 'aq-sensor-3-ikea PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.aq_sensor_3_ikea_pm2_5',
@@ -1166,7 +1166,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'a3a970ea-e09c-9c04-161b-94c934e21666_main_veryFineDustSensor_veryFineDustLevel_veryFineDustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[da_ac_airsensor_01001][sensor.eeomoniteo_peulreoseu_pm1-state]
@@ -1175,7 +1175,7 @@
       'device_class': 'pm1',
       'friendly_name': '에어모니터 플러스 PM1',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.eeomoniteo_peulreoseu_pm1',
@@ -1219,7 +1219,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'a3a970ea-e09c-9c04-161b-94c934e21666_main_dustSensor_dustLevel_dustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[da_ac_airsensor_01001][sensor.eeomoniteo_peulreoseu_pm10-state]
@@ -1228,7 +1228,7 @@
       'device_class': 'pm10',
       'friendly_name': '에어모니터 플러스 PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.eeomoniteo_peulreoseu_pm10',
@@ -1272,7 +1272,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'a3a970ea-e09c-9c04-161b-94c934e21666_main_dustSensor_fineDustLevel_fineDustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[da_ac_airsensor_01001][sensor.eeomoniteo_peulreoseu_pm2_5-state]
@@ -1281,7 +1281,7 @@
       'device_class': 'pm25',
       'friendly_name': '에어모니터 플러스 PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.eeomoniteo_peulreoseu_pm2_5',
@@ -3035,7 +3035,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'F8042E25-0E53-0000-0000-000000000000_main_dustSensor_dustLevel_dustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[da_ac_rac_100001][sensor.corridor_a_c_pm10-state]
@@ -3044,7 +3044,7 @@
       'device_class': 'pm10',
       'friendly_name': 'Corridor A/C PM10',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.corridor_a_c_pm10',
@@ -3088,7 +3088,7 @@
     'supported_features': 0,
     'translation_key': None,
     'unique_id': 'F8042E25-0E53-0000-0000-000000000000_main_dustSensor_fineDustLevel_fineDustLevel',
-    'unit_of_measurement': 'µg/m³',
+    'unit_of_measurement': 'μg/m³',
   })
 # ---
 # name: test_all_entities[da_ac_rac_100001][sensor.corridor_a_c_pm2_5-state]
@@ -3097,7 +3097,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Corridor A/C PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.corridor_a_c_pm2_5',

tests/components/vesync/snapshots/test_sensor.ambr

@@ -355,7 +355,7 @@
       'supported_features': 0,
       'translation_key': None,
       'unique_id': '400s-purifier-pm25',
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
   ])
 # ---
@@ -393,7 +393,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Air Purifier 400s PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.air_purifier_400s_pm2_5',
@@ -539,7 +539,7 @@
       'supported_features': 0,
       'translation_key': None,
       'unique_id': '600s-purifier-pm25',
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
   ])
 # ---
@@ -577,7 +577,7 @@
       'device_class': 'pm25',
       'friendly_name': 'Air Purifier 600s PM2.5',
       'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-      'unit_of_measurement': 'µg/m³',
+      'unit_of_measurement': 'μg/m³',
     }),
     'context': <ANY>,
     'entity_id': 'sensor.air_purifier_600s_pm2_5',

tests/components/xiaomi_ble/test_sensor.py

@@ -262,7 +262,7 @@ async def test_xiaomi_hhccjcy01(hass: HomeAssistant) -> None:
     cond_sensor_attribtes = cond_sensor.attributes
     assert cond_sensor.state == "599"
     assert cond_sensor_attribtes[ATTR_FRIENDLY_NAME] == "Plant Sensor 3E7A Conductivity"
-    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "µS/cm"
+    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "μS/cm"
     assert cond_sensor_attribtes[ATTR_STATE_CLASS] == "measurement"
 
     moist_sensor = hass.states.get("sensor.plant_sensor_3e7a_moisture")
@@ -351,7 +351,7 @@ async def test_xiaomi_hhccjcy01_not_connectable(hass: HomeAssistant) -> None:
     cond_sensor_attribtes = cond_sensor.attributes
     assert cond_sensor.state == "599"
     assert cond_sensor_attribtes[ATTR_FRIENDLY_NAME] == "Plant Sensor 3E7A Conductivity"
-    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "µS/cm"
+    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "μS/cm"
     assert cond_sensor_attribtes[ATTR_STATE_CLASS] == "measurement"
 
     moist_sensor = hass.states.get("sensor.plant_sensor_3e7a_moisture")
@@ -438,7 +438,7 @@ async def test_xiaomi_hhccjcy01_only_some_sources_connectable(
     cond_sensor_attribtes = cond_sensor.attributes
     assert cond_sensor.state == "599"
     assert cond_sensor_attribtes[ATTR_FRIENDLY_NAME] == "Plant Sensor 3E7A Conductivity"
-    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "µS/cm"
+    assert cond_sensor_attribtes[ATTR_UNIT_OF_MEASUREMENT] == "μS/cm"
     assert cond_sensor_attribtes[ATTR_STATE_CLASS] == "measurement"
 
     moist_sensor = hass.states.get("sensor.plant_sensor_3e7a_moisture")
@@ -653,7 +653,7 @@ async def test_hhccjcy10_uuid(hass: HomeAssistant) -> None:
     cond_sensor_attr = cond_sensor.attributes
     assert cond_sensor.state == "91"
     assert cond_sensor_attr[ATTR_FRIENDLY_NAME] == "Plant Sensor 5BFC Conductivity"
-    assert cond_sensor_attr[ATTR_UNIT_OF_MEASUREMENT] == "µS/cm"
+    assert cond_sensor_attr[ATTR_UNIT_OF_MEASUREMENT] == "μS/cm"
     assert cond_sensor_attr[ATTR_STATE_CLASS] == "measurement"
 
     moist_sensor = hass.states.get("sensor.plant_sensor_5bfc_moisture")

tests/pylint/conftest.py

@@ -138,3 +138,24 @@ def decorator_checker_fixture(hass_decorator, linter) -> BaseChecker:
     type_hint_checker = hass_decorator.HassDecoratorChecker(linter)
     type_hint_checker.module = "homeassistant.components.pylint_test"
     return type_hint_checker
+
+
+@pytest.fixture(name="hass_enforce_greek_micro_char", scope="package")
+def hass_enforce_greek_micro_checker_fixture() -> ModuleType:
+    """Fixture to the content for the hass_enforce_greek_micro_char check."""
+    return _load_plugin_from_file(
+        "hass_enforce_greek_micro_char",
+        "pylint/plugins/hass_enforce_greek_micro_char.py",
+    )
+
+
+@pytest.fixture(name="enforce_greek_micro_char_checker")
+def enforce_greek_micro_char_checker_fixture(
+    hass_enforce_greek_micro_char, linter
+) -> BaseChecker:
+    """Fixture to provide a hass_enforce_greek_micro_char checker."""
+    enforce_greek_micro_char_checker = (
+        hass_enforce_greek_micro_char.HassEnforceGreekMicroCharChecker(linter)
+    )
+    enforce_greek_micro_char_checker.module = "homeassistant.components.pylint_test"
+    return enforce_greek_micro_char_checker

tests/pylint/test_enforce_greek_micro_char.py

@@ -0,0 +1,164 @@
+"""Tests for pylint hass_enforce_greek_micro_char plugin."""
+
+from __future__ import annotations
+
+import astroid
+from pylint.checkers import BaseChecker
+from pylint.testutils.unittest_linter import UnittestLinter
+from pylint.utils.ast_walker import ASTWalker
+import pytest
+
+from . import assert_no_messages
+
+
+@pytest.mark.parametrize(
+    "code",
+    [
+        pytest.param(
+            # Test using the correct μ-sign \u03bc with annotation
+            """
+        CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "μg/m³"
+        """,
+            id="good_const_with_annotation",
+        ),
+        pytest.param(
+            # Test using the correct μ-sign \u03bc with annotation using unicode encoding
+            """
+        CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "\u03bcg/m³"
+        """,
+            id="good_unicode_const_with_annotation",
+        ),
+        pytest.param(
+            # Test using the correct μ-sign \u03bc without annotation
+            """
+        CONCENTRATION_MICROGRAMS_PER_CUBIC_METER = "μg/m³"
+        """,
+            id="good_const_without_annotation",
+        ),
+        pytest.param(
+            # Test using the correct μ-sign \u03bc in a StrEnum class
+            """
+            class UnitOfElectricPotential(StrEnum):
+                \"\"\"Electric potential units.\"\"\"
+
+                MICROVOLT = "μV"
+                MILLIVOLT = "mV"
+                VOLT = "V"
+                KILOVOLT = "kV"
+                MEGAVOLT = "MV"
+        """,
+            id="good_str_enum",
+        ),
+        pytest.param(
+            # Test using the correct μ-sign \u03bc in a sensor description dict
+            """
+            SENSOR_DESCRIPTION = {
+                "radiation_rate": AranetSensorEntityDescription(
+                    key="radiation_rate",
+                    translation_key="radiation_rate",
+                    name="Radiation Dose Rate",
+                    native_unit_of_measurement="μSv/h",
+                    state_class=SensorStateClass.MEASUREMENT,
+                    suggested_display_precision=2,
+                    scale=0.001,
+                ),
+            }
+            OTHER_DICT = {
+                "value_with_bad_mu_should_pass": "µ"
+            }
+        """,
+            id="good_sensor_description",
+        ),
+    ],
+)
+def test_enforce_greek_micro_char(
+    linter: UnittestLinter,
+    enforce_greek_micro_char_checker: BaseChecker,
+    code: str,
+) -> None:
+    """Good test cases."""
+    root_node = astroid.parse(code, "homeassistant.components.pylint_test")
+    walker = ASTWalker(linter)
+    walker.add_checker(enforce_greek_micro_char_checker)
+
+    with assert_no_messages(linter):
+        walker.walk(root_node)
+
+
+@pytest.mark.parametrize(
+    "code",
+    [
+        pytest.param(
+            # Test we can detect the legacy coding of μ \u00b5
+            # instead of recommended coding of μ \u03bc" with annotation
+            """
+            CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "µg/m³"
+        """,
+            id="bad_const_with_annotation",
+        ),
+        pytest.param(
+            # Test we can detect the unicode variant of the legacy coding of μ \u00b5
+            # instead of recommended coding of μ \u03bc" with annotation
+            """
+            CONCENTRATION_MICROGRAMS_PER_CUBIC_METER: Final = "\u00b5g/m³"
+        """,
+            id="bad_unicode_const_with_annotation",
+        ),
+        pytest.param(
+            # Test we can detect the legacy coding of μ \u00b5
+            # instead of recommended coding of μ \u03bc" without annotation
+            """
+            CONCENTRATION_MICROGRAMS_PER_CUBIC_METER = "µg/m³"
+        """,
+            id="bad_const_without_annotation",
+        ),
+        pytest.param(
+            # Test we can detect the legacy coding of μ \u00b5
+            # instead of recommended coding of μ \u03bc" in a StrEnum class
+            """
+            class UnitOfElectricPotential(StrEnum):
+                \"\"\"Electric potential units.\"\"\"
+
+                MICROVOLT = "µV"
+                MILLIVOLT = "mV"
+                VOLT = "V"
+                KILOVOLT = "kV"
+                MEGAVOLT = "MV"
+        """,
+            id="bad_str_enum",
+        ),
+        pytest.param(
+            # Test we can detect the legacy coding of μ \u00b5
+            # instead of recommended coding of μ \u03bc" in a sensor description dict
+            """
+            SENSOR_DESCRIPTION = {
+                "radiation_rate": AranetSensorEntityDescription(
+                    key="radiation_rate",
+                    translation_key="radiation_rate",
+                    name="Radiation Dose Rate",
+                    native_unit_of_measurement="µSv/h",
+                    state_class=SensorStateClass.MEASUREMENT,
+                    suggested_display_precision=2,
+                    scale=0.001,
+                ),
+            }
+        """,
+            id="bad_sensor_description",
+        ),
+    ],
+)
+def test_enforce_greek_micro_char_assign_bad(
+    linter: UnittestLinter,
+    enforce_greek_micro_char_checker: BaseChecker,
+    code: str,
+) -> None:
+    """Bad assignment test cases."""
+    root_node = astroid.parse(code, "homeassistant.components.pylint_test")
+    walker = ASTWalker(linter)
+    walker.add_checker(enforce_greek_micro_char_checker)
+
+    walker.walk(root_node)
+    messages = linter.release_messages()
+    assert len(messages) == 1
+    message = next(iter(messages))
+    assert message.msg_id == "hass-enforce-greek-micro-char"

tests/test_const.py

@@ -118,7 +118,7 @@ def test_deprecated_unit_of_conductivity_alias() -> None:
     """Test UnitOfConductivity deprecation."""
 
     # Test the deprecated members are aliases
-    assert set(const.UnitOfConductivity) == {"S/cm", "µS/cm", "mS/cm"}
+    assert set(const.UnitOfConductivity) == {"S/cm", "μS/cm", "mS/cm"}
 
 
 def test_deprecated_unit_of_conductivity_members(