Provide statistics device_class based on source entity and characteristic (#69710)

homeassistant/components/statistics/sensor.py

@@ -20,6 +20,7 @@ from homeassistant.components.sensor import (
     SensorStateClass,
 )
 from homeassistant.const import (
+    ATTR_DEVICE_CLASS,
     ATTR_UNIT_OF_MEASUREMENT,
     CONF_ENTITY_ID,
     CONF_NAME,
@@ -88,7 +89,7 @@ DEPRECATION_WARNING_CHARACTERISTIC = (
 )
 
 # Statistics supported by a sensor source (numeric)
-STATS_NUMERIC_SUPPORT = (
+STATS_NUMERIC_SUPPORT = {
     STAT_AVERAGE_LINEAR,
     STAT_AVERAGE_STEP,
     STAT_AVERAGE_TIMELESS,
@@ -110,26 +111,51 @@ STATS_NUMERIC_SUPPORT = (
     STAT_VALUE_MAX,
     STAT_VALUE_MIN,
     STAT_VARIANCE,
-)
+}
 
 # Statistics supported by a binary_sensor source
-STATS_BINARY_SUPPORT = (
+STATS_BINARY_SUPPORT = {
     STAT_AVERAGE_STEP,
     STAT_AVERAGE_TIMELESS,
     STAT_COUNT,
     STAT_MEAN,
-)
+}
 
-STATS_NOT_A_NUMBER = (
+STATS_NOT_A_NUMBER = {
     STAT_DATETIME_NEWEST,
     STAT_DATETIME_OLDEST,
     STAT_QUANTILES,
-)
+}
 
-STATS_DATETIME = (
+STATS_DATETIME = {
     STAT_DATETIME_NEWEST,
     STAT_DATETIME_OLDEST,
-)
+}
+
+# Statistics which retain the unit of the source entity
+STAT_NUMERIC_RETAIN_UNIT = {
+    STAT_AVERAGE_LINEAR,
+    STAT_AVERAGE_STEP,
+    STAT_AVERAGE_TIMELESS,
+    STAT_CHANGE,
+    STAT_DISTANCE_95P,
+    STAT_DISTANCE_99P,
+    STAT_DISTANCE_ABSOLUTE,
+    STAT_MEAN,
+    STAT_MEDIAN,
+    STAT_NOISINESS,
+    STAT_STANDARD_DEVIATION,
+    STAT_TOTAL,
+    STAT_VALUE_MAX,
+    STAT_VALUE_MIN,
+}
+
+# Statistics which produce percentage ratio from binary_sensor source entity
+STAT_BINARY_PERCENTAGE = {
+    STAT_AVERAGE_STEP,
+    STAT_AVERAGE_TIMELESS,
+    STAT_MEAN,
+}
 
 CONF_STATE_CHARACTERISTIC = "state_characteristic"
 CONF_SAMPLES_MAX_BUFFER_SIZE = "sampling_size"
@@ -336,30 +362,11 @@ class StatisticsSensor(SensorEntity):
     def _derive_unit_of_measurement(self, new_state: State) -> str | None:
         base_unit: str | None = new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
         unit: str | None
-        if self.is_binary and self._state_characteristic in (
+        if self.is_binary and self._state_characteristic in STAT_BINARY_PERCENTAGE:
-            STAT_AVERAGE_STEP,
-            STAT_AVERAGE_TIMELESS,
-            STAT_MEAN,
-        ):
             unit = "%"
         elif not base_unit:
             unit = None
-        elif self._state_characteristic in (
+        elif self._state_characteristic in STAT_NUMERIC_RETAIN_UNIT:
-            STAT_AVERAGE_LINEAR,
-            STAT_AVERAGE_STEP,
-            STAT_AVERAGE_TIMELESS,
-            STAT_CHANGE,
-            STAT_DISTANCE_95P,
-            STAT_DISTANCE_99P,
-            STAT_DISTANCE_ABSOLUTE,
-            STAT_MEAN,
-            STAT_MEDIAN,
-            STAT_NOISINESS,
-            STAT_STANDARD_DEVIATION,
-            STAT_TOTAL,
-            STAT_VALUE_MAX,
-            STAT_VALUE_MIN,
-        ):
             unit = base_unit
         elif self._state_characteristic in STATS_NOT_A_NUMBER:
             unit = None
@@ -374,8 +381,11 @@ class StatisticsSensor(SensorEntity):
         return unit
 
     @property
-    def device_class(self) -> Literal[SensorDeviceClass.TIMESTAMP] | None:
+    def device_class(self) -> SensorDeviceClass | None:
         """Return the class of this device."""
+        if self._state_characteristic in STAT_NUMERIC_RETAIN_UNIT:
+            _state = self.hass.states.get(self._source_entity_id)
+            return None if _state is None else _state.attributes.get(ATTR_DEVICE_CLASS)
         if self._state_characteristic in STATS_DATETIME:
             return SensorDeviceClass.TIMESTAMP
         return None

tests/components/statistics/test_sensor.py

@@ -8,10 +8,15 @@ from typing import Any
 from unittest.mock import patch
 
 from homeassistant import config as hass_config
-from homeassistant.components.sensor import ATTR_STATE_CLASS, SensorStateClass
+from homeassistant.components.sensor import (
+    ATTR_STATE_CLASS,
+    SensorDeviceClass,
+    SensorStateClass,
+)
 from homeassistant.components.statistics import DOMAIN as STATISTICS_DOMAIN
 from homeassistant.components.statistics.sensor import StatisticsSensor
 from homeassistant.const import (
+    ATTR_DEVICE_CLASS,
     ATTR_UNIT_OF_MEASUREMENT,
     SERVICE_RELOAD,
     STATE_UNAVAILABLE,
@@ -428,6 +433,61 @@ async def test_precision(hass: HomeAssistant):
     assert state.state == str(round(mean, 3))
 
 
+async def test_device_class(hass: HomeAssistant):
+    """Test device class, which depends on the source entity."""
+    assert await async_setup_component(
+        hass,
+        "sensor",
+        {
+            "sensor": [
+                {
+                    # Device class is carried over from source sensor for characteristics with same unit
+                    "platform": "statistics",
+                    "name": "test_source_class",
+                    "entity_id": "sensor.test_monitored",
+                    "state_characteristic": "mean",
+                },
+                {
+                    # Device class is set to None for characteristics with special meaning
+                    "platform": "statistics",
+                    "name": "test_none",
+                    "entity_id": "sensor.test_monitored",
+                    "state_characteristic": "count",
+                },
+                {
+                    # Device class is set to timestamp for datetime characteristics
+                    "platform": "statistics",
+                    "name": "test_timestamp",
+                    "entity_id": "sensor.test_monitored",
+                    "state_characteristic": "datetime_oldest",
+                },
+            ]
+        },
+    )
+    await hass.async_block_till_done()
+
+    for value in VALUES_NUMERIC:
+        hass.states.async_set(
+            "sensor.test_monitored",
+            str(value),
+            {
+                ATTR_UNIT_OF_MEASUREMENT: TEMP_CELSIUS,
+                ATTR_DEVICE_CLASS: SensorDeviceClass.TEMPERATURE,
+            },
+        )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.test_source_class")
+    assert state is not None
+    assert state.attributes.get(ATTR_DEVICE_CLASS) == SensorDeviceClass.TEMPERATURE
+    state = hass.states.get("sensor.test_none")
+    assert state is not None
+    assert state.attributes.get(ATTR_DEVICE_CLASS) is None
+    state = hass.states.get("sensor.test_timestamp")
+    assert state is not None
+    assert state.attributes.get(ATTR_DEVICE_CLASS) == SensorDeviceClass.TIMESTAMP
+
+
 async def test_state_class(hass: HomeAssistant):
     """Test state class, which depends on the characteristic configured."""
     assert await async_setup_component(