Fix handling of empty google_calendars.yaml file (#84909)

fixes undefined

homeassistant/components/google/__init__.py

@@ -327,7 +327,7 @@ def load_config(path: str) -> dict[str, Any]:
     calendars = {}
     try:
         with open(path, encoding="utf8") as file:
-            data = yaml.safe_load(file)
+            data = yaml.safe_load(file) or []
             for calendar in data:
                 calendars[calendar[CONF_CAL_ID]] = DEVICE_SCHEMA(calendar)
     except FileNotFoundError as err:

tests/components/google/conftest.py

@@ -121,7 +121,9 @@ def mock_calendars_yaml(
     calendars_config: list[dict[str, Any]],
 ) -> Generator[Mock, None, None]:
     """Fixture that prepares the google_calendars.yaml mocks."""
-    mocked_open_function = mock_open(read_data=yaml.dump(calendars_config))
+    mocked_open_function = mock_open(
+        read_data=yaml.dump(calendars_config) if calendars_config else None
+    )
     with patch("homeassistant.components.google.open", mocked_open_function):
         yield mocked_open_function
 

tests/components/google/test_init.py

@@ -192,6 +192,26 @@ async def test_calendar_yaml_error(
     assert hass.states.get(TEST_API_ENTITY)
 
 
+@pytest.mark.parametrize("calendars_config", [None])
+async def test_empty_calendar_yaml(
+    hass: HomeAssistant,
+    component_setup: ComponentSetup,
+    calendars_config: list[dict[str, Any]],
+    mock_calendars_yaml: None,
+    mock_calendars_list: ApiResult,
+    test_api_calendar: dict[str, Any],
+    mock_events_list: ApiResult,
+) -> None:
+    """Test an empty yaml file is equivalent to a missing yaml file."""
+    mock_calendars_list({"items": [test_api_calendar]})
+    mock_events_list({})
+
+    assert await component_setup()
+
+    assert not hass.states.get(TEST_YAML_ENTITY)
+    assert hass.states.get(TEST_API_ENTITY)
+
+
 async def test_init_calendar(
     hass: HomeAssistant,
     component_setup: ComponentSetup,