Restore state of template binary sensor with on or off delay (#67546)

homeassistant/components/template/binary_sensor.py

@@ -30,6 +30,9 @@ from homeassistant.const import (
     CONF_UNIQUE_ID,
     CONF_UNIT_OF_MEASUREMENT,
     CONF_VALUE_TEMPLATE,
+    STATE_ON,
+    STATE_UNAVAILABLE,
+    STATE_UNKNOWN,
 )
 from homeassistant.core import CALLBACK_TYPE, HomeAssistant, callback
 from homeassistant.exceptions import TemplateError
@@ -38,6 +41,7 @@ import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import async_generate_entity_id
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.event import async_call_later
+from homeassistant.helpers.restore_state import RestoreEntity
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
 
 from . import TriggerUpdateCoordinator
@@ -186,7 +190,7 @@ async def async_setup_platform(
     )
 
 
-class BinarySensorTemplate(TemplateEntity, BinarySensorEntity):
+class BinarySensorTemplate(TemplateEntity, BinarySensorEntity, RestoreEntity):
     """A virtual binary sensor that triggers from another sensor."""
 
     def __init__(
@@ -212,7 +216,14 @@ class BinarySensorTemplate(TemplateEntity, BinarySensorEntity):
         self._delay_off_raw = config.get(CONF_DELAY_OFF)
 
     async def async_added_to_hass(self):
-        """Register callbacks."""
+        """Restore state and register callbacks."""
+        if (
+            (self._delay_on_raw is not None or self._delay_off_raw is not None)
+            and (last_state := await self.async_get_last_state()) is not None
+            and last_state.state not in (STATE_UNKNOWN, STATE_UNAVAILABLE)
+        ):
+            self._state = last_state.state == STATE_ON
+
         self.add_template_attribute("_state", self._template, None, self._update_state)
 
         if self._delay_on_raw is not None:

tests/components/template/test_binary_sensor.py

@@ -15,11 +15,16 @@ from homeassistant.const import (
     STATE_UNAVAILABLE,
     STATE_UNKNOWN,
 )
-from homeassistant.core import Context, CoreState
+from homeassistant.core import Context, CoreState, State
 from homeassistant.helpers import entity_registry
+from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
 
-from tests.common import async_fire_time_changed
+from tests.common import (
+    assert_setup_component,
+    async_fire_time_changed,
+    mock_restore_cache,
+)
 
 ON = "on"
 OFF = "off"
@@ -914,6 +919,70 @@ async def test_availability_icon_picture(hass, start_ha, entity_id):
     }
 
 
+@pytest.mark.parametrize("count,domain", [(1, "template")])
+@pytest.mark.parametrize(
+    "config",
+    [
+        {
+            "template": {
+                "binary_sensor": {
+                    "name": "test",
+                    "state": "{{ states.sensor.test_state.state == 'on' }}",
+                },
+            },
+        },
+    ],
+)
+@pytest.mark.parametrize(
+    "extra_config, restored_state, initial_state",
+    [
+        ({}, ON, OFF),
+        ({}, OFF, OFF),
+        ({}, STATE_UNAVAILABLE, OFF),
+        ({}, STATE_UNKNOWN, OFF),
+        ({"delay_off": 5}, ON, ON),
+        ({"delay_off": 5}, OFF, OFF),
+        ({"delay_off": 5}, STATE_UNAVAILABLE, STATE_UNKNOWN),
+        ({"delay_off": 5}, STATE_UNKNOWN, STATE_UNKNOWN),
+        ({"delay_on": 5}, ON, ON),
+        ({"delay_on": 5}, OFF, OFF),
+        ({"delay_on": 5}, STATE_UNAVAILABLE, STATE_UNKNOWN),
+        ({"delay_on": 5}, STATE_UNKNOWN, STATE_UNKNOWN),
+    ],
+)
+async def test_restore_state(
+    hass, count, domain, config, extra_config, restored_state, initial_state
+):
+    """Test restoring template binary sensor."""
+
+    fake_state = State(
+        "binary_sensor.test",
+        restored_state,
+        {},
+    )
+    mock_restore_cache(hass, (fake_state,))
+    config = dict(config)
+    config["template"]["binary_sensor"].update(**extra_config)
+    with assert_setup_component(count, domain):
+        assert await async_setup_component(
+            hass,
+            domain,
+            config,
+        )
+
+        await hass.async_block_till_done()
+
+        context = Context()
+        hass.bus.async_fire("test_event", {"beer": 2}, context=context)
+        await hass.async_block_till_done()
+
+        await hass.async_start()
+        await hass.async_block_till_done()
+
+    state = hass.states.get("binary_sensor.test")
+    assert state.state == initial_state
+
+
 @pytest.mark.parametrize("count,domain", [(2, "template")])
 @pytest.mark.parametrize(
     "config",