feat(avatar): follow user language in replies

digital-avatar-app/backend/tests/test_chat_orchestration.py

@@ -5,7 +5,15 @@ from unittest.mock import Mock
 from fastapi import HTTPException
 
 from models import Avatar, User
-from routers.chat import _build_prompt, _iter_text_chunks, _match_standard_qa, _public_avatar_payload, _require_owned_avatar, _resolve_reply
+from routers.chat import (
+    _build_prompt,
+    _iter_text_chunks,
+    _match_standard_qa,
+    _public_avatar_payload,
+    _qa_requires_language_adaptation,
+    _require_owned_avatar,
+    _resolve_reply,
+)
 
 
 class ChatOrchestrationTests(unittest.TestCase):
@@ -50,6 +58,34 @@ class ChatOrchestrationTests(unittest.TestCase):
         self.assertEqual(result["answer"], "标准地址")
         fake_model.assert_not_called()
 
+    def test_cross_language_qa_is_faithfully_adapted_by_model(self):
+        fake_model = Mock(return_value="Our address is Test Road 1.")
+        fake_search = Mock(return_value=[])
+        result = _resolve_reply(
+            None,
+            self.avatar,
+            "Where is your office?",
+            [],
+            qa_pairs=[SimpleNamespace(question="Where is your office?", answer="地址是测试路1号。", enabled=True)],
+            search_fn=fake_search,
+            model_client=fake_model,
+        )
+
+        self.assertEqual(result["source"], "qa")
+        self.assertEqual(result["answer"], "Our address is Test Road 1.")
+        self.assertEqual(fake_model.call_args.kwargs["temperature"], 0.0)
+        system = fake_model.call_args.kwargs["messages"][0]["content"]
+        self.assertIn("已确认标准答案", system)
+        self.assertIn("地址是测试路1号", system)
+        self.assertIn("只使用该语言回答", system)
+        fake_search.assert_not_called()
+
+    def test_qa_language_adaptation_detects_common_writing_system_changes(self):
+        self.assertTrue(_qa_requires_language_adaptation("Hello", "你好"))
+        self.assertTrue(_qa_requires_language_adaptation("こんにちは", "你好"))
+        self.assertTrue(_qa_requires_language_adaptation("안녕하세요", "你好"))
+        self.assertFalse(_qa_requires_language_adaptation("你好", "您好"))
+
     def test_conversational_paraphrase_matches_standard_qa(self):
         for question in ("请问一下，你们公司在哪里呀？", "请问去你们那边怎么走"):
             with self.subTest(question=question):
@@ -106,6 +142,9 @@ class ChatOrchestrationTests(unittest.TestCase):
         self.assertIn("像熟人之间微信聊天一样", messages[0]["content"])
         self.assertIn("不隶属于任何机构", messages[0]["content"])
         self.assertIn("不要连续输出空行", messages[0]["content"])
+        self.assertIn("回答语言规则", messages[0]["content"])
+        self.assertIn("当前最后一条用户消息", messages[0]["content"])
+        self.assertIn("历史消息", messages[0]["content"])
 
     def test_prompt_blocks_ungrounded_factual_answers(self):
         messages = _build_prompt(self.avatar, [], "聊聊国际新闻", [])