Handle generic_thermostat state unavailable (#32852)

* fix sensor unavailable error

* fix climate.py

tests/components/generic_thermostat/test_climate.py

@@ -22,6 +22,8 @@ from homeassistant.const import (
     SERVICE_TURN_ON,
     STATE_OFF,
     STATE_ON,
+    STATE_UNAVAILABLE,
+    STATE_UNKNOWN,
     TEMP_CELSIUS,
     TEMP_FAHRENHEIT,
 )
@@ -271,6 +273,44 @@ async def test_sensor_bad_value(hass, setup_comp_2):
     assert temp == state.attributes.get("current_temperature")
 
 
+async def test_sensor_unknown(hass):
+    """Test when target sensor is Unknown."""
+    hass.states.async_set("sensor.unknown", STATE_UNKNOWN)
+    assert await async_setup_component(
+        hass,
+        "climate",
+        {
+            "climate": {
+                "platform": "generic_thermostat",
+                "name": "unknown",
+                "heater": ENT_SWITCH,
+                "target_sensor": "sensor.unknown",
+            }
+        },
+    )
+    state = hass.states.get("climate.unknown")
+    assert state.attributes.get("current_temperature") is None
+
+
+async def test_sensor_unavailable(hass):
+    """Test when target sensor is Unavailable."""
+    hass.states.async_set("sensor.unavailable", STATE_UNAVAILABLE)
+    assert await async_setup_component(
+        hass,
+        "climate",
+        {
+            "climate": {
+                "platform": "generic_thermostat",
+                "name": "unavailable",
+                "heater": ENT_SWITCH,
+                "target_sensor": "sensor.unavailable",
+            }
+        },
+    )
+    state = hass.states.get("climate.unavailable")
+    assert state.attributes.get("current_temperature") is None
+
+
 async def test_set_target_temp_heater_on(hass, setup_comp_2):
     """Test if target temperature turn heater on."""
     calls = _setup_switch(hass, False)