Implement suggested_display_precision for ESPHome (#147849)

homeassistant/components/esphome/sensor.py

@@ -81,6 +81,7 @@ class EsphomeSensor(EsphomeEntity[SensorInfo, SensorState], SensorEntity):
         # if the string is empty
         if unit_of_measurement := static_info.unit_of_measurement:
             self._attr_native_unit_of_measurement = unit_of_measurement
+        self._attr_suggested_display_precision = static_info.accuracy_decimals
         self._attr_device_class = try_parse_enum(
             SensorDeviceClass, static_info.device_class
         )
@@ -97,7 +98,7 @@ class EsphomeSensor(EsphomeEntity[SensorInfo, SensorState], SensorEntity):
             self._attr_state_class = _STATE_CLASSES.from_esphome(state_class)
 
     @property
-    def native_value(self) -> datetime | str | None:
+    def native_value(self) -> datetime | int | float | None:
         """Return the state of the entity."""
         if not self._has_state or (state := self._state).missing_state:
             return None
@@ -106,7 +107,7 @@ class EsphomeSensor(EsphomeEntity[SensorInfo, SensorState], SensorEntity):
             return None
         if self.device_class is SensorDeviceClass.TIMESTAMP:
             return dt_util.utc_from_timestamp(state_float)
-        return f"{state_float:.{self._static_info.accuracy_decimals}f}"
+        return state_float
 
 
 class EsphomeTextSensor(EsphomeEntity[TextSensorInfo, TextSensorState], SensorEntity):

tests/components/esphome/test_entity.py

@@ -375,7 +375,7 @@ async def test_deep_sleep_device(
     assert state.state == STATE_ON
     state = hass.states.get("sensor.test_my_sensor")
     assert state is not None
-    assert state.state == "123"
+    assert state.state == "123.0"
 
     await mock_device.mock_disconnect(False)
     await hass.async_block_till_done()
@@ -394,7 +394,7 @@ async def test_deep_sleep_device(
     assert state.state == STATE_ON
     state = hass.states.get("sensor.test_my_sensor")
     assert state is not None
-    assert state.state == "123"
+    assert state.state == "123.0"
 
     await mock_device.mock_disconnect(True)
     await hass.async_block_till_done()

tests/components/esphome/test_sensor.py

@@ -13,18 +13,28 @@ from aioesphomeapi import (
     TextSensorInfo,
     TextSensorState,
 )
+import pytest
 
 from homeassistant.components.sensor import (
     ATTR_STATE_CLASS,
     SensorDeviceClass,
     SensorStateClass,
+    async_rounded_state,
 )
 from homeassistant.const import (
     ATTR_DEVICE_CLASS,
     ATTR_ICON,
     ATTR_UNIT_OF_MEASUREMENT,
+    PERCENTAGE,
     STATE_UNKNOWN,
     EntityCategory,
+    UnitOfElectricCurrent,
+    UnitOfElectricPotential,
+    UnitOfEnergy,
+    UnitOfPower,
+    UnitOfPressure,
+    UnitOfTemperature,
+    UnitOfVolume,
 )
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import entity_registry as er
@@ -441,3 +451,63 @@ async def test_generic_numeric_sensor_empty_string_uom(
     assert state is not None
     assert state.state == "123"
     assert ATTR_UNIT_OF_MEASUREMENT not in state.attributes
+
+
+@pytest.mark.parametrize(
+    ("device_class", "unit_of_measurement", "state_value", "expected_precision"),
+    [
+        (SensorDeviceClass.TEMPERATURE, UnitOfTemperature.CELSIUS, 23.456, 1),
+        (SensorDeviceClass.TEMPERATURE, UnitOfTemperature.CELSIUS, 0.1, 1),
+        (SensorDeviceClass.TEMPERATURE, UnitOfTemperature.CELSIUS, -25.789, 1),
+        (SensorDeviceClass.POWER, UnitOfPower.WATT, 1234.56, 0),
+        (SensorDeviceClass.POWER, UnitOfPower.WATT, 1.23456, 3),
+        (SensorDeviceClass.POWER, UnitOfPower.WATT, 0.123, 3),
+        (SensorDeviceClass.ENERGY, UnitOfEnergy.WATT_HOUR, 1234.5, 0),
+        (SensorDeviceClass.ENERGY, UnitOfEnergy.WATT_HOUR, 12.3456, 2),
+        (SensorDeviceClass.VOLTAGE, UnitOfElectricPotential.VOLT, 230.45, 1),
+        (SensorDeviceClass.VOLTAGE, UnitOfElectricPotential.VOLT, 3.3, 1),
+        (SensorDeviceClass.CURRENT, UnitOfElectricCurrent.AMPERE, 15.678, 2),
+        (SensorDeviceClass.CURRENT, UnitOfElectricCurrent.AMPERE, 0.015, 3),
+        (SensorDeviceClass.ATMOSPHERIC_PRESSURE, UnitOfPressure.HPA, 1013.25, 1),
+        (SensorDeviceClass.PRESSURE, UnitOfPressure.BAR, 1.01325, 3),
+        (SensorDeviceClass.VOLUME, UnitOfVolume.LITERS, 45.67, 1),
+        (SensorDeviceClass.VOLUME, UnitOfVolume.LITERS, 4567.0, 0),
+        (SensorDeviceClass.HUMIDITY, PERCENTAGE, 87.654, 1),
+        (SensorDeviceClass.HUMIDITY, PERCENTAGE, 45.2, 1),
+        (SensorDeviceClass.BATTERY, PERCENTAGE, 95.2, 1),
+        (SensorDeviceClass.BATTERY, PERCENTAGE, 100.0, 1),
+    ],
+)
+async def test_suggested_display_precision_by_device_class(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_esphome_device: MockESPHomeDeviceType,
+    device_class: SensorDeviceClass,
+    unit_of_measurement: str,
+    state_value: float,
+    expected_precision: int,
+) -> None:
+    """Test suggested display precision for different device classes."""
+    entity_info = [
+        SensorInfo(
+            object_id="mysensor",
+            key=1,
+            name="my sensor",
+            unique_id="my_sensor",
+            accuracy_decimals=expected_precision,
+            device_class=device_class.value,
+            unit_of_measurement=unit_of_measurement,
+        )
+    ]
+    states = [SensorState(key=1, state=state_value)]
+    await mock_esphome_device(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        states=states,
+    )
+
+    state = hass.states.get("sensor.test_my_sensor")
+    assert state is not None
+    assert float(
+        async_rounded_state(hass, "sensor.test_my_sensor", state)
+    ) == pytest.approx(round(state_value, expected_precision))