feat(trading): support multi-item purchase intents

tests/test_site_interact.py

@@ -11,6 +11,7 @@ clear_cart 与 _dump_debug_snapshot 用不依赖 Playwright 的 fake page 覆盖
 """
 from __future__ import annotations
 
+import asyncio
 import json
 from pathlib import Path
 from typing import Any
@@ -39,6 +40,7 @@ from app.trading.worker.site_interact import (
     _DELETE_BUTTON_SELECTOR,
     _extract_error_message,
     _extract_purchase_fields,
+    _normalize_intent_items,
     _OrderListAccumulator,
     _parse_checkout_summary,
     _parse_initial_state,
@@ -70,6 +72,82 @@ def _wrap_state(state: dict[str, Any]) -> str:
     )
 
 
+# ---- 下单意图兼容 ----
+
+
+def test_normalize_intent_items_accepts_legacy_single_item():
+    assert _normalize_intent_items({
+        "item_url": "https://item.rakuten.co.jp/shop/x/",
+        "quantity": 2,
+    }) == [{
+        "item_url": "https://item.rakuten.co.jp/shop/x/",
+        "quantity": 2,
+        "variant_id": None,
+        "choice": None,
+    }]
+
+
+def test_normalize_intent_items_accepts_multiple_items_and_string_urls():
+    assert _normalize_intent_items({
+        "items": [
+            {"item_url": "https://item.rakuten.co.jp/shop/x/", "quantity": 2},
+            "https://item.rakuten.co.jp/shop/y/",
+        ]
+    }) == [
+        {
+            "item_url": "https://item.rakuten.co.jp/shop/x/",
+            "quantity": 2,
+            "variant_id": None,
+            "choice": None,
+        },
+        {
+            "item_url": "https://item.rakuten.co.jp/shop/y/",
+            "quantity": 1,
+            "variant_id": None,
+            "choice": None,
+        },
+    ]
+
+
+def test_normalize_intent_items_rejects_empty_items():
+    with pytest.raises(InvalidRequestError):
+        _normalize_intent_items({"items": []})
+
+
+async def test_add_to_cart_processes_all_items_and_keeps_legacy_state():
+    site = SiteInteractor.__new__(SiteInteractor)
+    site._lock = asyncio.Lock()
+    site._per_task_state = {}
+    calls: list[dict[str, Any]] = []
+
+    async def fake_add(**kwargs):
+        calls.append(kwargs)
+        index = len(calls)
+        return {
+            "item_id": str(index),
+            "shop_bid": "shop",
+            "basket_domain": "https://basket",
+            "response_html": f"html-{index}",
+            "screenshot": b"",
+        }
+
+    site._add_to_cart_with_fields = fake_add
+    snapshot = await site.add_to_cart(_make_task(intent={
+        "items": [
+            {"item_url": "https://item.rakuten.co.jp/shop/x/"},
+            {"item_url": "https://item.rakuten.co.jp/shop/y/", "quantity": 3},
+        ]
+    }))
+    assert [call["item_url"] for call in calls] == [
+        "https://item.rakuten.co.jp/shop/x/",
+        "https://item.rakuten.co.jp/shop/y/",
+    ]
+    assert calls[1]["quantity"] == 3
+    assert site._per_task_state["t1"]["item_id"] == "1"
+    assert site._per_task_state["t1"]["item_ids"] == ["1", "2"]
+    assert snapshot.html == "html-2"
+
+
 # ---- _parse_initial_state ----