Add subscribe preview feature helper to labs (#161778)

tests/components/labs/test_init.py

@@ -9,8 +9,10 @@ import pytest
 
 from homeassistant.components.labs import (
     EVENT_LABS_UPDATED,
+    EventLabsUpdatedData,
     async_is_preview_feature_enabled,
     async_listen,
+    async_subscribe_preview_feature,
     async_update_preview_feature,
 )
 from homeassistant.components.labs.const import DOMAIN, LABS_DATA
@@ -441,6 +443,96 @@ async def test_async_listen_helper(hass: HomeAssistant) -> None:
     assert len(listener_calls) == 1
 
 
+async def test_async_subscribe_preview_feature_helper(hass: HomeAssistant) -> None:
+    """Test async_subscribe_preview_feature helper."""
+    hass.config.components.add("kitchen_sink")
+
+    assert await async_setup_component(hass, DOMAIN, {})
+    await hass.async_block_till_done()
+
+    calls: list[EventLabsUpdatedData] = []
+
+    async def listener(event_data: EventLabsUpdatedData) -> None:
+        """Test listener callback."""
+        calls.append(event_data)
+
+    unsub = async_subscribe_preview_feature(
+        hass,
+        domain="kitchen_sink",
+        preview_feature="special_repair",
+        listener=listener,
+    )
+
+    # Fire event for the subscribed feature
+    hass.bus.async_fire(
+        EVENT_LABS_UPDATED,
+        {
+            "domain": "kitchen_sink",
+            "preview_feature": "special_repair",
+            "enabled": True,
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert len(calls) == 1
+    assert calls[0]["enabled"] is True
+
+    # Fire event for a different feature - should not trigger listener
+    hass.bus.async_fire(
+        EVENT_LABS_UPDATED,
+        {
+            "domain": "kitchen_sink",
+            "preview_feature": "other_feature",
+            "enabled": True,
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert len(calls) == 1
+
+    # Fire event for a different domain - should not trigger listener
+    hass.bus.async_fire(
+        EVENT_LABS_UPDATED,
+        {
+            "domain": "other_domain",
+            "preview_feature": "special_repair",
+            "enabled": True,
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert len(calls) == 1
+
+    # Fire event with enabled=False
+    hass.bus.async_fire(
+        EVENT_LABS_UPDATED,
+        {
+            "domain": "kitchen_sink",
+            "preview_feature": "special_repair",
+            "enabled": False,
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert len(calls) == 2
+    assert calls[1]["enabled"] is False
+
+    # Test unsubscribe
+    unsub()
+
+    hass.bus.async_fire(
+        EVENT_LABS_UPDATED,
+        {
+            "domain": "kitchen_sink",
+            "preview_feature": "special_repair",
+            "enabled": True,
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert len(calls) == 2
+
+
 async def test_async_update_preview_feature(
     hass: HomeAssistant, hass_storage: dict[str, Any]
 ) -> None: