Add sensor platform to backup integration (#138663)

* add sensor platform to backup integration

* adjust namings, remove system integration flag

* add first simple test

* apply review comments

* fix test

* add sensor tests

* adjustements to use backup helper

* remove obsolet async_get_manager from init

* unsubscribe from events on entry unload

* add configuration_url

* fix doc string

* fix sensor tests

* mark async_unsubscribe as callback

* set integration_type service

* extend sensor test

* set integration_type on correct integration :)

* fix after online conflict resolution

* add sensor update tests

* simplify the sensor update tests

* avoid io during tests

* Add comment

---------

Co-authored-by: Martin Hjelmare <marhje52@gmail.com>

homeassistant/components/backup/sensor.py

@@ -0,0 +1,75 @@
+"""Sensor platform for Home Assistant Backup integration."""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from datetime import datetime
+
+from homeassistant.components.sensor import (
+    SensorDeviceClass,
+    SensorEntity,
+    SensorEntityDescription,
+)
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddConfigEntryEntitiesCallback
+
+from .coordinator import BackupConfigEntry, BackupCoordinatorData
+from .entity import BackupManagerEntity
+from .manager import BackupManagerState
+
+
+@dataclass(kw_only=True, frozen=True)
+class BackupSensorEntityDescription(SensorEntityDescription):
+    """Description for Home Assistant Backup sensor entities."""
+
+    value_fn: Callable[[BackupCoordinatorData], str | datetime | None]
+
+
+BACKUP_MANAGER_DESCRIPTIONS = (
+    BackupSensorEntityDescription(
+        key="backup_manager_state",
+        translation_key="backup_manager_state",
+        device_class=SensorDeviceClass.ENUM,
+        options=[state.value for state in BackupManagerState],
+        value_fn=lambda data: data.backup_manager_state,
+    ),
+    BackupSensorEntityDescription(
+        key="next_scheduled_automatic_backup",
+        translation_key="next_scheduled_automatic_backup",
+        device_class=SensorDeviceClass.TIMESTAMP,
+        value_fn=lambda data: data.next_scheduled_automatic_backup,
+    ),
+    BackupSensorEntityDescription(
+        key="last_successful_automatic_backup",
+        translation_key="last_successful_automatic_backup",
+        device_class=SensorDeviceClass.TIMESTAMP,
+        value_fn=lambda data: data.last_successful_automatic_backup,
+    ),
+)
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    config_entry: BackupConfigEntry,
+    async_add_entities: AddConfigEntryEntitiesCallback,
+) -> None:
+    """Sensor set up for backup config entry."""
+
+    coordinator = config_entry.runtime_data
+
+    async_add_entities(
+        BackupManagerSensor(coordinator, description)
+        for description in BACKUP_MANAGER_DESCRIPTIONS
+    )
+
+
+class BackupManagerSensor(BackupManagerEntity, SensorEntity):
+    """Sensor to track backup manager state."""
+
+    entity_description: BackupSensorEntityDescription
+
+    @property
+    def native_value(self) -> str | datetime | None:
+        """Return native value of entity."""
+        return self.entity_description.value_fn(self.coordinator.data)