chore: create Multica handoff checkpoint

app/tests/test_mentor_stream.py

@@ -103,6 +103,35 @@ class MentorStreamTests(unittest.TestCase):
             )
         self.assertEqual(chunks, ["first", " second"])
 
+    def test_follow_up_block_is_collected_without_leaking_into_answer(self):
+        lines = [
+            'data: {"choices":[{"delta":{"content":"先看承接，再等确认。\\n<XIAOBAI_FOL"}}]}\n'.encode(),
+            'data: {"choices":[{"delta":{"content":"LOW_UPS>\\n[\\"什么信号代表承接有效？\\",\\"这个判断何时失效？\\"]\\n</XIAOBAI_FOLLOW_UPS>"}}]}\n'.encode(),
+            b"data: [DONE]\n",
+        ]
+        follow_ups: list[str] = []
+        with patch(
+            "backend.llm.transport.urllib.request.urlopen",
+            return_value=FakeStreamResponse(lines),
+        ):
+            chunks = list(
+                stream_with_mentor(
+                    self.skill,
+                    {},
+                    "question",
+                    [],
+                    "key",
+                    "https://example.test/v1",
+                    "model",
+                    follow_ups=follow_ups,
+                )
+            )
+        self.assertEqual("".join(chunks), "先看承接，再等确认。\n")
+        self.assertEqual(
+            follow_ups,
+            ["什么信号代表承接有效？", "这个判断何时失效？"],
+        )
+
 
 if __name__ == "__main__":
     unittest.main()