This helps to make sure that:

* The documentation is up-to-date.
* The documentation examples can be run as is.
* Most of the features are covered by the documentation, ensured by test coverage.

#### Apps and docs at the same time

If you run the examples with, e.g.:

<div class="termy">

```console
$ uvicorn tutorial001:app --reload

That would refer to some package above `app/`, with its own file `__init__.py`, etc. But we don't have that. So, that would throw an error in our example. 🚨

But now you know how it works, so you can use relative imports in your own apps no matter how complex they are. 🤓

### Add some custom `tags`, `responses`, and `dependencies`

We are not adding the prefix `/items` nor the `tags=["items"]` to each *path operation* because we added them to the `APIRouter`.

* Die Dokumentationsbeispiele ohne Änderung ausgeführt werden können.
* Die meisten Funktionalitäten durch die Dokumentation abgedeckt werden, sichergestellt durch die Testabdeckung.

#### Gleichzeitig Apps und Dokumentation

Wenn Sie die Beispiele ausführen, mit z. B.:

<div class="termy">

```console
$ uvicorn tutorial001:app --reload

    link: https://rightcode.co.jp/blog/information-technology/fastapi-tutorial-todo-apps-admin-page-improvement
    title: '【第4回】FastAPIチュートリアル: toDoアプリを作ってみよう【管理者ページ改良編】'
  - author: ライトコードメディア編集部
    author_link: https://rightcode.co.jp/author/jun
    link: https://rightcode.co.jp/blog/information-technology/fastapi-tutorial-todo-apps-authentication-user-registration
    title: '【第3回】FastAPIチュートリアル: toDoアプリを作ってみよう【認証・ユーザ登録編】'

<div class="termy">

```console
$ typer --install-completion

zsh completion installed in /home/user/.bashrc.
Completion will take effect once you restart the terminal.
```

</div>

### Apps et documentation en même temps

Si vous exécutez les exemples avec, par exemple :

<div class="termy">

```console
$ uvicorn tutorial001:app --reload

<a href="https://platform.sh/try-it-now/?utm_source=fastapi-signup&utm_medium=banner&utm_campaign=FastAPI-signup-June-2023" target="_blank" title="Build, run and scale your apps on a modern, reliable, and secure PaaS."><img src="https://fastapi.tiangolo.com/img/sponsors/platform-sh.png"></a>

And normally this **load balancer** would be able to handle requests that go to *other* apps in your cluster (e.g. to a different domain, or under a different URL path prefix), and would transmit that communication to the right containers for *that other* application running in your cluster.

### One Process per Container