from fastapi import FastAPI
from fastapi.routing import APIRoute

app = FastAPI()


@app.get("/items/")
async def read_items():
    return [{"item_id": "Foo"}]


def use_route_names_as_operation_ids(app: FastAPI) -> None:
    """
    Simplify operation IDs so that generated API clients have simpler function
    names.

    Should be called only after all routes have been added.
    """
    for route in app.routes:

I consider **FastAPI** a "spiritual successor" to APIStar, while improving and increasing the features, typing system, and other parts, based on the learnings from all these previous tools.

///

## Used by **FastAPI** { #used-by-fastapi }

# Use Old 403 Authentication Error Status Codes { #use-old-403-authentication-error-status-codes }

Before FastAPI version `0.122.0`, when the integrated security utilities returned an error to the client after a failed authentication, they used the HTTP status code `403 Forbidden`.

{* ../../docs_src/wsgi/tutorial001_py39.py hl[2:3,3] *}

## Confira { #check-it }

Agora, todas as requisições sob o path `/v1/` serão manipuladas pela aplicação Flask.

E o resto será manipulado pelo **FastAPI**.

Se você rodar a aplicação e ir até <a href="http://localhost:8000/v1/" class="external-link" target="_blank">http://localhost:8000/v1/</a>, você verá o retorno do Flask:

```txt
Hello, World from Flask!
```

Antes da versão `0.122.0` do FastAPI, quando os utilitários de segurança integrados retornavam um erro ao cliente após uma falha na autenticação, eles usavam o código de status HTTP `403 Forbidden`.

from fastapi.testclient import TestClient

from docs_src.path_params.tutorial002_py39 import app

client = TestClient(app)


def test_get_items():
    response = client.get("/items/1")
    assert response.status_code == 200, response.text
    assert response.json() == {"item_id": 1}


def test_get_items_invalid_id():
    response = client.get("/items/item1")
    assert response.status_code == 422, response.text

# 异步测试

您已经了解了如何使用 `TestClient` 测试 **FastAPI** 应用程序。但是到目前为止，您只了解了如何编写同步测试，而没有使用 `async` 异步函数。

在测试中能够使用异步函数可能会很有用，比如当您需要异步查询数据库的时候。想象一下，您想要测试向 FastAPI 应用程序发送请求，然后验证您的后端是否成功在数据库中写入了正确的数据，与此同时您使用了异步的数据库的库。

让我们看看如何才能实现这一点。

## pytest.mark.anyio

如果我们想在测试中调用异步函数，那么我们的测试函数必须是异步的。 AnyIO 为此提供了一个简洁的插件，它允许我们指定一些测试函数要异步调用。

## HTTPX

即使您的 **FastAPI** 应用程序使用普通的 `def` 函数而不是 `async def` ，它本质上仍是一个 `async` 异步应用程序。

import importlib

import pytest
from fastapi.testclient import TestClient


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial001_py39"),
        pytest.param("tutorial010_py39"),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.custom_response.{request.param}")
    client = TestClient(mod.app)
    return client

# Usar los códigos de estado antiguos 403 para errores de autenticación { #use-old-403-authentication-error-status-codes }

Antes de FastAPI versión `0.122.0`, cuando las utilidades de seguridad integradas devolvían un error al cliente después de una autenticación fallida, usaban el código de estado HTTP `403 Forbidden`.

import pytest
from fastapi.testclient import TestClient

from docs_src.path_params.tutorial003_py39 import app

client = TestClient(app)


@pytest.mark.parametrize(
    ("user_id", "expected_response"),
    [
        ("me", {"user_id": "the current user"}),
        ("alice", {"user_id": "alice"}),
    ],
)
def test_get_users(user_id: str, expected_response: dict):
    response = client.get(f"/users/{user_id}")