Start LangGraph backend migration foundation

test/api/fastgpt.http

@@ -1,8 +1,11 @@
-GET http://101.89.151.141:3000
+@fastgptBaseUrl = http://127.0.0.1:3000
+@fastgptApiKey = replace-with-local-api-key
+
+GET {{fastgptBaseUrl}}
 ###
-POST http://101.89.151.141:3000/api/v1/chat/completions
+POST {{fastgptBaseUrl}}/api/v1/chat/completions
 content-type: application/json
-Authorization: Bearer fastgpt-xCH4CaEoNEyVtq7fkBEI5UP3O6sABKdpGszTtSYk4R2TVW5VgrPp1YPfuLX1iH
+Authorization: Bearer {{fastgptApiKey}}
 
 {
 
@@ -23,4 +26,4 @@ content-type: application/json; charset=utf-8
 etag: "s14v22uu1g5f"
 content-length: 219
 date: Fri, 20 Jun 2025 02:37:16 GMT
-connection: close
+connection: close

test/api/test_chat_sse_contract.py

@@ -0,0 +1,116 @@
+import json
+
+import pytest
+
+from src.api.endpoints import chat
+from src.backends.chat import ChatInput, ChatResult, FormUpdate, TextDelta
+from src.schemas.models import ProcessRequest_chat
+
+
+def make_request(**overrides):
+    payload = {
+        "sessionId": "session-001",
+        "timeStamp": "20260726120000",
+        "text": "发生了交通事故",
+        "needFormUpdate": True,
+    }
+    payload.update(overrides)
+    return ProcessRequest_chat(**payload)
+
+
+async def response_text(response):
+    chunks = []
+    async for chunk in response.body_iterator:
+        chunks.append(chunk.decode() if isinstance(chunk, bytes) else chunk)
+    return "".join(chunks)
+
+
+def parse_sse(body):
+    events = []
+    for block in body.strip().split("\n\n"):
+        lines = block.splitlines()
+        event = lines[0].removeprefix("event: ")
+        data = json.loads(lines[1].removeprefix("data: "))
+        events.append((event, data))
+    return events
+
+
+class OrderedBackend:
+    async def stream(self, chat_input: ChatInput):
+        yield TextDelta("<sta")
+        yield TextDelta("te>1002</state>")
+        yield FormUpdate({"jdcsl": 2})
+        yield TextDelta("第一句。")
+        yield TextDelta("第二句。")
+
+    async def complete(self, chat_input: ChatInput):
+        return ChatResult("<state>1002</state>第一句。第二句。", "1002", {"jdcsl": 2})
+
+
+class MissingPrefixBackend:
+    async def stream(self, chat_input: ChatInput):
+        yield TextDelta("没有状态前缀")
+
+    async def complete(self, chat_input: ChatInput):
+        return ChatResult("没有状态前缀")
+
+
+@pytest.mark.asyncio
+async def test_sse_success_event_order_and_cardinality():
+    response = await chat(make_request(), stream=True, backend=OrderedBackend())
+    events = parse_sse(await response_text(response))
+    names = [name for name, _ in events]
+
+    assert names == [
+        "stage_code",
+        "formUpdate",
+        "text_delta",
+        "text_delta",
+        "done",
+    ]
+    assert names.count("stage_code") == 1
+    assert names.count("formUpdate") == 1
+    assert names.count("done") == 1
+    assert "error" not in names
+    assert "".join(data["text"] for name, data in events if name == "text_delta") == (
+        "第一句。第二句。"
+    )
+
+
+@pytest.mark.asyncio
+async def test_use_text_chunk_only_changes_delta_boundaries():
+    request = make_request(useTextChunk=True)
+    response = await chat(request, stream=True, backend=OrderedBackend())
+    events = parse_sse(await response_text(response))
+
+    assert "".join(data["text"] for name, data in events if name == "text_delta") == (
+        "第一句。第二句。"
+    )
+    assert [name for name, _ in events].count("done") == 1
+
+
+@pytest.mark.asyncio
+async def test_missing_stream_prefix_characterizes_current_legacy_behavior():
+    response = await chat(
+        make_request(needFormUpdate=False),
+        stream=True,
+        backend=MissingPrefixBackend(),
+    )
+    events = parse_sse(await response_text(response))
+
+    assert [name for name, _ in events] == ["text_delta", "done"]
+    assert events[0][1]["text"] == "没有状态前缀"
+
+
+@pytest.mark.asyncio
+async def test_missing_non_stream_prefix_returns_compatible_business_error():
+    response = await chat(
+        make_request(needFormUpdate=False),
+        stream=False,
+        backend=MissingPrefixBackend(),
+    )
+
+    assert response.code == "500"
+    assert response.outputText == ""
+    assert response.nextStageCode == ""
+    assert response.msg == "大模型服务返回消息不完整"

test/api/test_info_contract.py

@@ -0,0 +1,145 @@
+import json
+
+import pytest
+
+from src.api import endpoints
+from src.api.endpoints import get_info, set_info
+from src.schemas.models import ProcessRequest_get, ProcessRequest_set
+
+
+class FakeResponse:
+    def __init__(self, payload):
+        self._payload = payload
+
+    def raise_for_status(self):
+        return None
+
+    def json(self):
+        return self._payload
+
+
+class FakeInfoClient:
+    def __init__(self, state):
+        self.state = state
+        self.completion_calls = []
+
+    async def create_chat_completion(self, **kwargs):
+        self.completion_calls.append(kwargs)
+        if "variables" in kwargs:
+            self.state = kwargs["variables"]["state"]
+        return FakeResponse({"newVariables": {"state": self.state}})
+
+
+@pytest.fixture
+def skip_helper_record_deletion(monkeypatch):
+    calls = []
+
+    async def fake_delete(client, session_id):
+        calls.append(session_id)
+
+    monkeypatch.setattr(endpoints, "delete_last_two_chat_records", fake_delete)
+    return calls
+
+
+def make_set_request(**overrides):
+    payload = {
+        "sessionId": "session-001",
+        "timeStamp": "20260726120000",
+        "key": "hphm1",
+        "value": "<PLATE_1>",
+    }
+    payload.update(overrides)
+    return ProcessRequest_set(**payload)
+
+
+def make_get_request(**overrides):
+    payload = {
+        "sessionId": "session-001",
+        "timeStamp": "20260726120000",
+        "key": "all",
+    }
+    payload.update(overrides)
+    return ProcessRequest_get(**payload)
+
+
+@pytest.mark.asyncio
+async def test_set_info_reads_then_writes_fastgpt_state(
+    skip_helper_record_deletion,
+):
+    client = FakeInfoClient({"hphm1": "<PLATE_OLD>", "jdcsl": 1})
+
+    response = await set_info(make_set_request(), client=client)
+
+    assert response.code == "200"
+    assert client.state == {"hphm1": "<PLATE_1>", "jdcsl": 1}
+    assert len(client.completion_calls) == 2
+    assert client.completion_calls[1]["variables"]["state"] == client.state
+    assert skip_helper_record_deletion == ["session-001", "session-001"]
+
+
+@pytest.mark.asyncio
+async def test_set_info_include_input_info_keeps_legacy_magic_payload(
+    skip_helper_record_deletion,
+):
+    client = FakeInfoClient({})
+
+    await set_info(make_set_request(includeInputInfo=True), client=client)
+
+    message = client.completion_calls[0]["messages"][0]["content"]
+    assert message == '<setInfo>{"key": "hphm1", "value": "<PLATE_1>"}</setInfo>'
+
+
+@pytest.mark.asyncio
+async def test_get_info_all_keeps_json_string_and_boolean_encoding(
+    skip_helper_record_deletion,
+):
+    client = FakeInfoClient(
+        {
+            "ywrysw": False,
+            "ywfjdc": True,
+            "jdcsl": 2,
+            "xm1": "<PERSON_1>",
+            "hphm1": "<PLATE_1>",
+            "xm2": "<PERSON_2>",
+        }
+    )
+
+    response = await get_info(make_get_request(), client=client)
+    value = json.loads(response.value)
+
+    assert response.code == "200"
+    assert isinstance(response.value, str)
+    assert value["acdinfo"]["ywrysw"] == "0"
+    assert value["acdinfo"]["ywfjdc"] == "1"
+    assert value["acdinfo"]["jdcsl"] == 2
+    assert value["acdhuman1"]["xm1"] == "<PERSON_1>"
+    assert value["acdhuman2"]["xm2"] == "<PERSON_2>"
+    assert skip_helper_record_deletion == ["session-001"]
+
+
+@pytest.mark.asyncio
+async def test_get_info_unknown_key_returns_json_encoded_empty_string(
+    skip_helper_record_deletion,
+):
+    client = FakeInfoClient({})
+
+    response = await get_info(
+        make_get_request(key="unknown_legacy_key"),
+        client=client,
+    )
+
+    assert response.code == "200"
+    assert response.value == '""'
+
+
+@pytest.mark.asyncio
+async def test_get_info_fastgpt_shape_error_keeps_legacy_business_error():
+    class InvalidClient:
+        async def create_chat_completion(self, **kwargs):
+            return FakeResponse({})
+
+    response = await get_info(make_get_request(), client=InvalidClient())
+
+    assert response.code == "500"
+    assert response.value == ""
+    assert response.msg == "大模型服务器无响应"