from fastapi import APIRouter, FastAPI
from fastapi.testclient import TestClient


def test_redirect_slashes_enabled():
    app = FastAPI()
    router = APIRouter()

    @router.get("/hello/")
    def hello_page() -> str:
        return "Hello, World!"

    app.include_router(router)

    client = TestClient(app)

    response = client.get("/hello/", follow_redirects=False)
    assert response.status_code == 200

We are importing the submodule `items` directly, instead of importing just its variable `router`.

This is because we also have another variable named `router` in the submodule `users`.

If we had imported one after the other, like:

```Python
from .routers.items import router
from .routers.users import router
```

import pytest
from fastapi import APIRouter, FastAPI
from fastapi.exceptions import FastAPIError
from fastapi.testclient import TestClient

app = FastAPI()

router = APIRouter()


@router.get("")
def get_empty():
    return ["OK"]


app.include_router(router, prefix="/prefix")


client = TestClient(app)


def test_use_empty():
    with client:
        response = client.get("/prefix")

    assert response.json() == expected_response


def test_route_classes():
    routes = {}
    for r in app.router.routes:
        assert isinstance(r, Route)
        routes[r.path] = r
    assert getattr(routes["/a/"], "x_type") == "A"  # noqa: B009
    assert getattr(routes["/a/b/"], "x_type") == "B"  # noqa: B009
    assert getattr(routes["/a/b/c/"], "x_type") == "C"  # noqa: B009


def test_openapi_schema():

            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():

    response = client_nested.post("/outer/strict/items/", json={"key": "value"})
    assert response.status_code == 200


def test_default_inner_accepts_json_content_type():
    response = client_nested.post("/outer/default/items/", json={"key": "value"})
    assert response.status_code == 200


# Strict app -> lax outer router -> strict inner router

app_mixed = FastAPI(strict_content_type=True)

## Including Routers

When declaring routers, prefer to add router level parameters like prefix, tags, etc. to the router itself, instead of in `include_router()`.

Do this:

```python
from fastapi import APIRouter, FastAPI

app = FastAPI()

router = APIRouter(prefix="/items", tags=["items"])


@router.get("/")
async def list_items():
    return []

            return

        wrapper = self.receive_wrapper(receive)
        await self.app(scope, wrapper, send)


@router.post("/middleware")
def run_middleware(file: UploadFile = File(..., description="Big File")):
    return {"message": "OK"}


app.include_router(router)
app.add_middleware(ContentSizeLimitMiddleware, max_content_size=2**8)


client = TestClient(app)

        if responses is None:
            responses = {}
        for route in router.routes:
            if isinstance(route, APIRoute):
                combined_responses = {**responses, **route.responses}
                use_response_class = get_value_or_default(
                    route.response_class,
                    router.default_response_class,
                    default_response_class,

///

### Add the callback router { #add-the-callback-router }

At this point you have the *callback path operation(s)* needed (the one(s) that the *external developer*  should implement in the *external API*) in the callback router you created above.

Now use the parameter `callbacks` in *your API's path operation decorator* to pass the attribute `.routes` (that's actually just a `list` of routes/*path operations*) from that callback router: