test(langchain): add real HTTP server support for agent invoke tests

Add _start_server function to launch actual FastAPI servers for integration testing,
modify request functions to accept both app objects and server URLs,
and update test fixtures to use real HTTP connections instead of ASGI transport.

This enables more realistic testing of agent invoke methods using actual HTTP requests
while maintaining backward compatibility with ASGI transport for non-streaming tests.

The changes affect test_agent_invoke_methods.py with new server startup logic,
enhanced request handling, and proper server cleanup in test fixtures.

test(langchain): 为代理调用测试添加真实 HTTP 服务器支持

添加 _start_server 函数以启动实际的 FastAPI 服务器进行集成测试，
修改请求函数以接受 app 对象和服务器 URL，
并更新测试 fixture 以使用真实的 HTTP 连接而不是 ASGI 传输。

这使得使用实际 HTTP 请求对代理调用方法进行更真实的测试
同时保持与 ASGI 传输的向后兼容性以用于非流式测试。

这些更改影响 test_agent_invoke_methods.py 中的新服务器启动逻辑、
增强的请求处理和测试 fixture 中的适当服务器清理。

Change-Id: Icb5b09c2d588021cf72749658b1d07237fc1ef9c
Signed-off-by: OhYee <oyohyee@oyohyee.com>

Author: OhYee

tests/unittests/integration/langchain/test_agent_invoke_methods.py

@@ -81,6 +81,39 @@ def _sse(data: Dict[str, Any]) -> str:
     return f"data: {json.dumps(data, ensure_ascii=False)}\n\n"
 
 
+def _start_server(app: FastAPI) -> tuple:
+    """启动 FastAPI 服务器并返回 base_url
+
+    Returns:
+        tuple: (base_url, server, thread)
+    """
+
+    # 添加健康检查端点
+    @app.get("/health")
+    async def health():
+        return {"status": "ok"}
+
+    port = _find_free_port()
+    config = uvicorn.Config(
+        app, host="127.0.0.1", port=port, log_level="warning"
+    )
+    server = uvicorn.Server(config)
+
+    thread = threading.Thread(target=server.run, daemon=True)
+    thread.start()
+
+    base_url = f"http://127.0.0.1:{port}"
+    # 等待服务器启动
+    for _ in range(50):
+        try:
+            httpx.get(f"{base_url}/health", timeout=0.2)
+            break
+        except Exception:
+            time.sleep(0.1)
+
+    return base_url, server, thread
+
+
 def _build_mock_openai_app() -> FastAPI:
     """构建本地 OpenAI 协议兼容的简单服务"""
     app = FastAPI()
@@ -297,20 +330,36 @@ def parse_sse_events(content: str) -> List[Dict[str, Any]]:
 
 
 async def request_agui_events(
-    server_app,
+    server_url_or_app: Union[str, FastAPI],
     messages: List[Dict[str, str]],
     stream: bool = True,
 ) -> List[Dict[str, Any]]:
-    """发送 AG-UI 请求并返回事件列表"""
-    async with httpx.AsyncClient(
-        transport=httpx.ASGITransport(app=server_app),
-        base_url="http://test",
-    ) as client:
-        response = await client.post(
-            "/ag-ui/agent",
-            json={"messages": messages, "stream": stream},
-            timeout=60.0,
-        )
+    """发送 AG-UI 请求并返回事件列表
+
+    Args:
+        server_url_or_app: 服务器 URL (如 "http://127.0.0.1:8000") 或 FastAPI app 对象
+        messages: 消息列表
+        stream: 是否流式响应
+    """
+    if isinstance(server_url_or_app, str):
+        # 使用真实的 HTTP 连接
+        async with httpx.AsyncClient(base_url=server_url_or_app) as client:
+            response = await client.post(
+                "/ag-ui/agent",
+                json={"messages": messages, "stream": stream},
+                timeout=60.0,
+            )
+    else:
+        # 使用 ASGITransport (用于非流式测试)
+        async with httpx.AsyncClient(
+            transport=httpx.ASGITransport(app=server_url_or_app),
+            base_url="http://test",
+        ) as client:
+            response = await client.post(
+                "/ag-ui/agent",
+                json={"messages": messages, "stream": stream},
+                timeout=60.0,
+            )
 
     assert response.status_code == 200
     return parse_sse_events(response.text)
@@ -670,26 +719,42 @@ def assert_openai_tool_call_response(
 
 
 async def request_openai_events(
-    server_app,
+    server_url_or_app: Union[str, FastAPI],
     messages: List[Dict[str, str]],
     stream: bool = True,
 ) -> Union[List[Dict[str, Any]], Dict[str, Any]]:
-    """发送 OpenAI 协议请求并返回流式事件列表或响应"""
+    """发送 OpenAI 协议请求并返回流式事件列表或响应
+
+    Args:
+        server_url_or_app: 服务器 URL (如 "http://127.0.0.1:8000") 或 FastAPI app 对象
+        messages: 消息列表
+        stream: 是否流式响应
+    """
     payload: Dict[str, Any] = {
         "model": "mock-model",
         "messages": messages,
         "stream": stream,
     }
 
-    async with httpx.AsyncClient(
-        transport=httpx.ASGITransport(app=server_app),
-        base_url="http://test",
-    ) as client:
-        response = await client.post(
-            "/openai/v1/chat/completions",
-            json=payload,
-            timeout=60.0,
-        )
+    if isinstance(server_url_or_app, str):
+        # 使用真实的 HTTP 连接
+        async with httpx.AsyncClient(base_url=server_url_or_app) as client:
+            response = await client.post(
+                "/openai/v1/chat/completions",
+                json=payload,
+                timeout=60.0,
+            )
+    else:
+        # 使用 ASGITransport (用于非流式测试)
+        async with httpx.AsyncClient(
+            transport=httpx.ASGITransport(app=server_url_or_app),
+            base_url="http://test",
+        ) as client:
+            response = await client.post(
+                "/openai/v1/chat/completions",
+                json=payload,
+                timeout=60.0,
+            )
 
     assert response.status_code == 200
 
@@ -779,7 +844,16 @@ async def generator():
         return generator()
 
     server = AgentRunServer(invoke_agent=invoke_agent)
-    return server.app
+    app = server.app
+
+    # 启动真实的 HTTP 服务器
+    base_url, uvicorn_server, thread = _start_server(app)
+
+    yield base_url
+
+    # 清理服务器
+    uvicorn_server.should_exit = True
+    thread.join(timeout=5)
 
 
 # =============================================================================
@@ -1643,7 +1717,16 @@ async def generator():
                 return await agent.ainvoke(cast(Any, input_data))
 
         server = AgentRunServer(invoke_agent=invoke_agent)
-        return server.app
+        app = server.app
+
+        # 启动真实的 HTTP 服务器
+        base_url, uvicorn_server, thread = _start_server(app)
+
+        yield base_url
+
+        # 清理服务器
+        uvicorn_server.should_exit = True
+        thread.join(timeout=5)
 
     @pytest.mark.parametrize(
         "case_key,prompt",
@@ -1704,7 +1787,16 @@ def generator():
                 return agent.invoke(cast(Any, input_data))
 
         server = AgentRunServer(invoke_agent=invoke_agent)
-        return server.app
+        app = server.app
+
+        # 启动真实的 HTTP 服务器
+        base_url, uvicorn_server, thread = _start_server(app)
+
+        yield base_url
+
+        # 清理服务器
+        uvicorn_server.should_exit = True
+        thread.join(timeout=5)
 
     @pytest.mark.parametrize(
         "case_key,prompt",
@@ -1762,7 +1854,16 @@ async def generator():
             return generator()
 
         server = AgentRunServer(invoke_agent=invoke_agent)
-        return server.app
+        app = server.app
+
+        # 启动真实的 HTTP 服务器
+        base_url, uvicorn_server, thread = _start_server(app)
+
+        yield base_url
+
+        # 清理服务器
+        uvicorn_server.should_exit = True
+        thread.join(timeout=5)
 
     @pytest.fixture
     def server_app_async(self, agent_model):
@@ -1796,7 +1897,16 @@ async def generator():
             return generator()
 
         server = AgentRunServer(invoke_agent=invoke_agent)
-        return server.app
+        app = server.app
+
+        # 启动真实的 HTTP 服务器
+        base_url, uvicorn_server, thread = _start_server(app)
+
+        yield base_url
+
+        # 清理服务器
+        uvicorn_server.should_exit = True
+        thread.join(timeout=5)
 
     @pytest.mark.parametrize(
         "case_key,prompt",