Store preferred border agent ID in thread dataset store (#98375)

tests/components/thread/test_dataset_store.py

@@ -319,12 +319,17 @@ async def test_loading_datasets_from_storage(
                     "tlv": DATASET_3,
                 },
             ],
+            "preferred_border_agent_id": "230C6A1AC57F6F4BE262ACF32E5EF52C",
             "preferred_dataset": "id1",
         },
     }
 
     store = await dataset_store.async_get_store(hass)
     assert len(store.datasets) == 3
+    assert (
+        store.async_get_preferred_border_agent_id()
+        == "230C6A1AC57F6F4BE262ACF32E5EF52C"
+    )
     assert store.preferred_dataset == "id1"
 
 
@@ -512,3 +517,34 @@ async def test_migrate_drop_duplicate_datasets_preferred(
         f"Dropped duplicated Thread dataset '{DATASET_1_LARGER_TIMESTAMP}' "
         f"(duplicate of preferred dataset '{DATASET_1}')"
     ) in caplog.text
+
+
+async def test_migrate_set_default_border_agent_id(
+    hass: HomeAssistant, hass_storage: dict[str, Any], caplog
+) -> None:
+    """Test migrating the dataset store adds default border agent."""
+    hass_storage[dataset_store.STORAGE_KEY] = {
+        "version": 1,
+        "minor_version": 2,
+        "data": {
+            "datasets": [
+                {
+                    "created": "2023-02-02T09:41:13.746514+00:00",
+                    "id": "id1",
+                    "source": "source_1",
+                    "tlv": DATASET_1,
+                },
+            ],
+            "preferred_dataset": "id1",
+        },
+    }
+
+    store = await dataset_store.async_get_store(hass)
+    assert store.async_get_preferred_border_agent_id() is None
+
+
+async def test_preferred_border_agent_id(hass: HomeAssistant) -> None:
+    """Test get and set the preferred border agent ID."""
+    assert await dataset_store.async_get_preferred_border_agent_id(hass) is None
+    await dataset_store.async_set_preferred_border_agent_id(hass, "blah")
+    assert await dataset_store.async_get_preferred_border_agent_id(hass) == "blah"

tests/components/thread/test_websocket_api.py

@@ -200,6 +200,35 @@ async def test_list_get_dataset(
     assert msg["error"] == {"code": "not_found", "message": "unknown dataset"}
 
 
+async def test_preferred_border_agent_id(
+    hass: HomeAssistant, hass_ws_client: WebSocketGenerator
+) -> None:
+    """Test setting and getting the preferred border agent ID."""
+    assert await async_setup_component(hass, DOMAIN, {})
+    await hass.async_block_till_done()
+
+    client = await hass_ws_client(hass)
+
+    await client.send_json_auto_id({"type": "thread/get_preferred_border_agent_id"})
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {"border_agent_id": None}
+
+    await client.send_json_auto_id(
+        {"type": "thread/set_preferred_border_agent_id", "border_agent_id": "blah"}
+    )
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] is None
+
+    await client.send_json_auto_id({"type": "thread/get_preferred_border_agent_id"})
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {"border_agent_id": "blah"}
+
+    assert await dataset_store.async_get_preferred_border_agent_id(hass) == "blah"
+
+
 async def test_set_preferred_dataset(
     hass: HomeAssistant, hass_ws_client: WebSocketGenerator
 ) -> None: