Add restore temperature to modbus climate (#50963)

* Add restore temperature to climate.

* please mypy.

* Review 2.

homeassistant/components/modbus/climate.py

@@ -20,6 +20,7 @@ from homeassistant.const import (
     TEMP_FAHRENHEIT,
 )
 from homeassistant.core import HomeAssistant
+from homeassistant.helpers.restore_state import RestoreEntity
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
 
 from .base_platform import BasePlatform
@@ -98,7 +99,7 @@ async def async_setup_platform(
     async_add_entities(entities)
 
 
-class ModbusThermostat(BasePlatform, ClimateEntity):
+class ModbusThermostat(BasePlatform, RestoreEntity, ClimateEntity):
     """Representation of a Modbus Thermostat."""
 
     def __init__(
@@ -131,6 +132,9 @@ class ModbusThermostat(BasePlatform, ClimateEntity):
     async def async_added_to_hass(self):
         """Handle entity which will be added."""
         await self.async_base_added_to_hass()
+        state = await self.async_get_last_state()
+        if state and state.attributes.get(ATTR_TEMPERATURE):
+            self._target_temperature = float(state.attributes[ATTR_TEMPERATURE])
 
     @property
     def supported_features(self):

tests/components/modbus/test_climate.py

@@ -2,16 +2,25 @@
 import pytest
 
 from homeassistant.components.climate import DOMAIN as CLIMATE_DOMAIN
+from homeassistant.components.climate.const import HVAC_MODE_AUTO
 from homeassistant.components.modbus.const import (
     CONF_CLIMATES,
     CONF_CURRENT_TEMP,
     CONF_DATA_COUNT,
     CONF_TARGET_TEMP,
 )
-from homeassistant.const import CONF_NAME, CONF_SCAN_INTERVAL, CONF_SLAVE
+from homeassistant.const import (
+    ATTR_TEMPERATURE,
+    CONF_NAME,
+    CONF_SCAN_INTERVAL,
+    CONF_SLAVE,
+)
+from homeassistant.core import State
 
 from .conftest import ReadResult, base_config_test, base_test, prepare_service_update
 
+from tests.common import mock_restore_cache
+
 
 @pytest.mark.parametrize(
     "do_options",
@@ -101,3 +110,34 @@ async def test_service_climate_update(hass, mock_pymodbus):
         "homeassistant", "update_entity", {"entity_id": entity_id}, blocking=True
     )
     assert hass.states.get(entity_id).state == "auto"
+
+
+async def test_restore_state_climate(hass):
+    """Run test for sensor restore state."""
+
+    climate_name = "test_climate"
+    test_temp = 37
+    entity_id = f"{CLIMATE_DOMAIN}.{climate_name}"
+    test_value = State(entity_id, 35)
+    test_value.attributes = {ATTR_TEMPERATURE: test_temp}
+    config_sensor = {
+        CONF_NAME: climate_name,
+        CONF_TARGET_TEMP: 117,
+        CONF_CURRENT_TEMP: 117,
+    }
+    mock_restore_cache(
+        hass,
+        (test_value,),
+    )
+    await base_config_test(
+        hass,
+        config_sensor,
+        climate_name,
+        CLIMATE_DOMAIN,
+        CONF_CLIMATES,
+        None,
+        method_discovery=True,
+    )
+    state = hass.states.get(entity_id)
+    assert state.state == HVAC_MODE_AUTO
+    assert state.attributes[ATTR_TEMPERATURE] == test_temp