Add variants for `custom_request_and_route/tutorial003`

docs/en/docs/how-to/custom-request-and-route.md

@@ -102,8 +102,8 @@ If an exception occurs, the`Request` instance will still be in scope, so we can
 
 You can also set the `route_class` parameter of an `APIRouter`:
 
-{* ../../docs_src/custom_request_and_route/tutorial003.py hl[26] *}
+{* ../../docs_src/custom_request_and_route/tutorial003_py310.py hl[26] *}
 
 In this example, the *path operations* under the `router` will use the custom `TimedRoute` class, and will have an extra `X-Response-Time` header in the response with the time it took to generate the response:
 
-{* ../../docs_src/custom_request_and_route/tutorial003.py hl[13:20] *}
+{* ../../docs_src/custom_request_and_route/tutorial003_py310.py hl[13:20] *}

docs_src/custom_request_and_route/tutorial003_py310.py

@@ -0,0 +1,39 @@
+import time
+from collections.abc import Callable
+
+from fastapi import APIRouter, FastAPI, Request, Response
+from fastapi.routing import APIRoute
+
+
+class TimedRoute(APIRoute):
+    def get_route_handler(self) -> Callable:
+        original_route_handler = super().get_route_handler()
+
+        async def custom_route_handler(request: Request) -> Response:
+            before = time.time()
+            response: Response = await original_route_handler(request)
+            duration = time.time() - before
+            response.headers["X-Response-Time"] = str(duration)
+            print(f"route duration: {duration}")
+            print(f"route response: {response}")
+            print(f"route response headers: {response.headers}")
+            return response
+
+        return custom_route_handler
+
+
+app = FastAPI()
+router = APIRouter(route_class=TimedRoute)
+
+
+@app.get("/")
+async def not_timed():
+    return {"message": "Not timed"}
+
+
+@router.get("/timed")
+async def timed():
+    return {"message": "It's the time of my life"}
+
+
+app.include_router(router)

tests/test_tutorial/test_custom_request_and_route/test_tutorial003.py

@@ -1,17 +1,32 @@
+import importlib
+
+import pytest
 from fastapi.testclient import TestClient
 
-from docs_src.custom_request_and_route.tutorial003 import app
+from tests.utils import needs_py310
+
+
+@pytest.fixture(
+    name="client",
+    params=[
+        pytest.param("tutorial003"),
+        pytest.param("tutorial003_py310", marks=needs_py310),
+    ],
+)
+def get_client(request: pytest.FixtureRequest):
+    mod = importlib.import_module(f"docs_src.custom_request_and_route.{request.param}")
 
-client = TestClient(app)
+    client = TestClient(mod.app)
+    return client
 
 
-def test_get():
+def test_get(client: TestClient):
     response = client.get("/")
     assert response.json() == {"message": "Not timed"}
     assert "X-Response-Time" not in response.headers
 
 
-def test_get_timed():
+def test_get_timed(client: TestClient):
     response = client.get("/timed")
     assert response.json() == {"message": "It's the time of my life"}
     assert "X-Response-Time" in response.headers