Handle empty strings for ESPHome UOMs (#96556)

homeassistant/components/esphome/number.py

@@ -63,7 +63,10 @@ class EsphomeNumber(EsphomeEntity[NumberInfo, NumberState], NumberEntity):
         self._attr_native_min_value = static_info.min_value
         self._attr_native_max_value = static_info.max_value
         self._attr_native_step = static_info.step
-        self._attr_native_unit_of_measurement = static_info.unit_of_measurement
+        # protobuf doesn't support nullable strings so we need to check
+        # if the string is empty
+        if unit_of_measurement := static_info.unit_of_measurement:
+            self._attr_native_unit_of_measurement = unit_of_measurement
         if mode := static_info.mode:
             self._attr_mode = NUMBER_MODES.from_esphome(mode)
         else:

homeassistant/components/esphome/sensor.py

@@ -76,7 +76,10 @@ class EsphomeSensor(EsphomeEntity[SensorInfo, SensorState], SensorEntity):
         super()._on_static_info_update(static_info)
         static_info = self._static_info
         self._attr_force_update = static_info.force_update
-        self._attr_native_unit_of_measurement = static_info.unit_of_measurement
+        # protobuf doesn't support nullable strings so we need to check
+        # 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_device_class = try_parse_enum(
             SensorDeviceClass, static_info.device_class
         )

tests/components/esphome/test_number.py

@@ -15,7 +15,7 @@ from homeassistant.components.number import (
     DOMAIN as NUMBER_DOMAIN,
     SERVICE_SET_VALUE,
 )
-from homeassistant.const import ATTR_ENTITY_ID, STATE_UNKNOWN
+from homeassistant.const import ATTR_ENTITY_ID, ATTR_UNIT_OF_MEASUREMENT, STATE_UNKNOWN
 from homeassistant.core import HomeAssistant
 
 
@@ -89,3 +89,36 @@ async def test_generic_number_nan(
     state = hass.states.get("number.test_mynumber")
     assert state is not None
     assert state.state == STATE_UNKNOWN
+
+
+async def test_generic_number_with_unit_of_measurement_as_empty_string(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_generic_device_entry,
+) -> None:
+    """Test a generic number entity with nan state."""
+    entity_info = [
+        NumberInfo(
+            object_id="mynumber",
+            key=1,
+            name="my number",
+            unique_id="my_number",
+            max_value=100,
+            min_value=0,
+            step=1,
+            unit_of_measurement="",
+            mode=ESPHomeNumberMode.SLIDER,
+        )
+    ]
+    states = [NumberState(key=1, state=42)]
+    user_service = []
+    await mock_generic_device_entry(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        user_service=user_service,
+        states=states,
+    )
+    state = hass.states.get("number.test_mynumber")
+    assert state is not None
+    assert state.state == "42"
+    assert ATTR_UNIT_OF_MEASUREMENT not in state.attributes

tests/components/esphome/test_sensor.py

@@ -13,7 +13,7 @@ from aioesphomeapi import (
 )
 
 from homeassistant.components.sensor import ATTR_STATE_CLASS, SensorStateClass
-from homeassistant.const import ATTR_ICON, STATE_UNKNOWN
+from homeassistant.const import ATTR_ICON, ATTR_UNIT_OF_MEASUREMENT, STATE_UNKNOWN
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.entity import EntityCategory
@@ -275,3 +275,30 @@ async def test_generic_text_sensor(
     state = hass.states.get("sensor.test_mysensor")
     assert state is not None
     assert state.state == "i am a teapot"
+
+
+async def test_generic_numeric_sensor_empty_string_uom(
+    hass: HomeAssistant, mock_client: APIClient, mock_generic_device_entry
+) -> None:
+    """Test a generic numeric sensor that has an empty string as the uom."""
+    entity_info = [
+        SensorInfo(
+            object_id="mysensor",
+            key=1,
+            name="my sensor",
+            unique_id="my_sensor",
+            unit_of_measurement="",
+        )
+    ]
+    states = [SensorState(key=1, state=123, missing_state=False)]
+    user_service = []
+    await mock_generic_device_entry(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        user_service=user_service,
+        states=states,
+    )
+    state = hass.states.get("sensor.test_mysensor")
+    assert state is not None
+    assert state.state == "123"
+    assert ATTR_UNIT_OF_MEASUREMENT not in state.attributes