Allow core integrations to describe their triggers (#147075)

Co-authored-by: Abílio Costa <abmantis@users.noreply.github.com>

tests/components/websocket_api/test_commands.py

@@ -2,6 +2,7 @@
 
 import asyncio
 from copy import deepcopy
+import io
 import logging
 from typing import Any
 from unittest.mock import ANY, AsyncMock, Mock, patch
@@ -19,6 +20,7 @@ from homeassistant.components.websocket_api.auth import (
 )
 from homeassistant.components.websocket_api.commands import (
     ALL_SERVICE_DESCRIPTIONS_JSON_CACHE,
+    ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE,
 )
 from homeassistant.components.websocket_api.const import FEATURE_COALESCE_MESSAGES, URL
 from homeassistant.config_entries import ConfigEntryState
@@ -28,9 +30,10 @@ from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
 from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 from homeassistant.helpers.event import async_track_state_change_event
-from homeassistant.loader import async_get_integration
+from homeassistant.loader import Integration, async_get_integration
 from homeassistant.setup import async_set_domains_to_be_loaded, async_setup_component
 from homeassistant.util.json import json_loads
+from homeassistant.util.yaml.loader import parse_yaml
 
 from tests.common import (
     MockConfigEntry,
@@ -707,6 +710,91 @@ async def test_get_services(
     assert hass.data[ALL_SERVICE_DESCRIPTIONS_JSON_CACHE] is old_cache
 
 
+@patch("annotatedyaml.loader.load_yaml")
+@patch.object(Integration, "has_triggers", return_value=True)
+async def test_subscribe_triggers(
+    mock_has_triggers: Mock,
+    mock_load_yaml: Mock,
+    hass: HomeAssistant,
+    websocket_client: MockHAClientWebSocket,
+) -> None:
+    """Test trigger_platforms/subscribe command."""
+    sun_trigger_descriptions = """
+        sun: {}
+        """
+    tag_trigger_descriptions = """
+        tag: {}
+        """
+
+    def _load_yaml(fname, secrets=None):
+        if fname.endswith("sun/triggers.yaml"):
+            trigger_descriptions = sun_trigger_descriptions
+        elif fname.endswith("tag/triggers.yaml"):
+            trigger_descriptions = tag_trigger_descriptions
+        else:
+            raise FileNotFoundError
+        with io.StringIO(trigger_descriptions) as file:
+            return parse_yaml(file)
+
+    mock_load_yaml.side_effect = _load_yaml
+
+    assert await async_setup_component(hass, "sun", {})
+    assert await async_setup_component(hass, "system_health", {})
+    await hass.async_block_till_done()
+
+    assert ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE not in hass.data
+
+    await websocket_client.send_json_auto_id({"type": "trigger_platforms/subscribe"})
+
+    # Test start subscription with initial event
+    msg = await websocket_client.receive_json()
+    assert msg == {"id": 1, "result": None, "success": True, "type": "result"}
+    msg = await websocket_client.receive_json()
+    assert msg == {"event": {"sun": {"fields": {}}}, "id": 1, "type": "event"}
+
+    old_cache = hass.data[ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE]
+
+    # Test we receive an event when a new platform is loaded, if it has descriptions
+    assert await async_setup_component(hass, "calendar", {})
+    assert await async_setup_component(hass, "tag", {})
+    await hass.async_block_till_done()
+    msg = await websocket_client.receive_json()
+    assert msg == {
+        "event": {"tag": {"fields": {}}},
+        "id": 1,
+        "type": "event",
+    }
+
+    # Initiate a second subscription to check the cache is updated because of the new
+    # trigger
+    await websocket_client.send_json_auto_id({"type": "trigger_platforms/subscribe"})
+    msg = await websocket_client.receive_json()
+    assert msg == {"id": 2, "result": None, "success": True, "type": "result"}
+    msg = await websocket_client.receive_json()
+    assert msg == {
+        "event": {"sun": {"fields": {}}, "tag": {"fields": {}}},
+        "id": 2,
+        "type": "event",
+    }
+
+    assert hass.data[ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE] is not old_cache
+
+    # Initiate a third subscription to check the cache is not updated because no new
+    # trigger was added
+    old_cache = hass.data[ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE]
+    await websocket_client.send_json_auto_id({"type": "trigger_platforms/subscribe"})
+    msg = await websocket_client.receive_json()
+    assert msg == {"id": 3, "result": None, "success": True, "type": "result"}
+    msg = await websocket_client.receive_json()
+    assert msg == {
+        "event": {"sun": {"fields": {}}, "tag": {"fields": {}}},
+        "id": 3,
+        "type": "event",
+    }
+
+    assert hass.data[ALL_TRIGGER_DESCRIPTIONS_JSON_CACHE] is old_cache
+
+
 async def test_get_config(
     hass: HomeAssistant, websocket_client: MockHAClientWebSocket
 ) -> None: