Add `state_class = MEASUREMENT` to Derivative sensor (#88408)

* Add `state_class = MEASUREMENT` to Derivative sensor

One line change per title.

* Update sensor.py

* Update tests for Derivative Sensor

homeassistant/components/derivative/sensor.py

@@ -8,7 +8,11 @@ from typing import TYPE_CHECKING
 
 import voluptuous as vol
 
-from homeassistant.components.sensor import PLATFORM_SCHEMA, SensorEntity
+from homeassistant.components.sensor import (
+    PLATFORM_SCHEMA,
+    SensorEntity,
+    SensorStateClass,
+)
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
@@ -131,6 +135,7 @@ class DerivativeSensor(RestoreEntity, SensorEntity):
 
     _attr_icon = ICON
     _attr_should_poll = False
+    _attr_state_class = SensorStateClass.MEASUREMENT
 
     def __init__(
         self,

tests/components/derivative/test_sensor.py

@@ -4,6 +4,7 @@ from math import sin
 import random
 from unittest.mock import patch
 
+from homeassistant.components.sensor import ATTR_STATE_CLASS, SensorStateClass
 from homeassistant.const import UnitOfPower, UnitOfTime
 from homeassistant.core import HomeAssistant
 from homeassistant.setup import async_setup_component
@@ -78,6 +79,7 @@ async def setup_tests(hass, config, times, values, expected_state):
     assert state is not None
 
     assert round(float(state.state), config["sensor"]["round"]) == expected_state
+    assert state.attributes.get(ATTR_STATE_CLASS) is SensorStateClass.MEASUREMENT
 
     return state