Allow adding items Picnic shopping cart by searching (#102862)

Co-authored-by: Robert Resch <robert@resch.dev>

tests/components/picnic/conftest.py

@@ -1,4 +1,5 @@
 """Conftest for Picnic tests."""
+from collections.abc import Awaitable, Callable
 import json
 from unittest.mock import MagicMock, patch
 
@@ -9,6 +10,9 @@ from homeassistant.const import CONF_ACCESS_TOKEN
 from homeassistant.core import HomeAssistant
 
 from tests.common import MockConfigEntry, load_fixture
+from tests.typing import WebSocketGenerator
+
+ENTITY_ID = "todo.mock_title_shopping_cart"
 
 
 @pytest.fixture
@@ -50,3 +54,42 @@ async def init_integration(
     await hass.async_block_till_done()
 
     return mock_config_entry
+
+
+@pytest.fixture
+def ws_req_id() -> Callable[[], int]:
+    """Fixture for incremental websocket requests."""
+
+    id = 0
+
+    def next_id() -> int:
+        nonlocal id
+        id += 1
+        return id
+
+    return next_id
+
+
+@pytest.fixture
+async def get_items(
+    hass_ws_client: WebSocketGenerator, ws_req_id: Callable[[], int]
+) -> Callable[[], Awaitable[dict[str, str]]]:
+    """Fixture to fetch items from the todo websocket."""
+
+    async def get() -> list[dict[str, str]]:
+        # Fetch items using To-do platform
+        client = await hass_ws_client()
+        id = ws_req_id()
+        await client.send_json(
+            {
+                "id": id,
+                "type": "todo/item/list",
+                "entity_id": ENTITY_ID,
+            }
+        )
+        resp = await client.receive_json()
+        assert resp.get("id") == id
+        assert resp.get("success")
+        return resp.get("result", {}).get("items", [])
+
+    return get