for key, value in build_config.items():
        context.config.build_config[key] = value
    # Get main dependencies
    dependencies: List[str] = metadata.get("dependencies", [])
    # Add optional dependencies to the default dependencies for this (non-slim) package
    for include_optional in include_optional_dependencies:
        optional_dependencies_group = optional_dependencies.get(include_optional, [])

```Python hl_lines="3"
{!../../../docs_src/app_testing/test_main.py!}
```

...and have the code for the tests just like before.

## Testing: extended example

Now let's extend this example and add more details to see how to test different parts.

### Extended **FastAPI** app file

Let's continue with the same file structure as before:

```
.
├── app
│   ├── __init__.py
│   ├── main.py

    * If you didn't use FastAPI and used Starlette directly (or another tool, like Sanic, Flask, Responder, etc) you would have to implement all the data validation and serialization...

* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.
    * This will be used by the **automatic docs**.
    * It will also be used by automatic client code generation tools.

But most importantly:

And it's also used internally when mounting sub-applications.

## Proxy with a stripped path prefix

Having a proxy with a stripped path prefix, in this case, means that you could declare a path at `/app` in your code, but then, you add a layer on top (the proxy) that would put your **FastAPI** application under a path like `/api/v1`.

In this case, the original path `/app` would actually be served at `/api/v1/app`.

after compilation to JavaScript, it cannot rely on the types to define validation, serialization and documentation at the same time. Due to this and some design decisions, to get validation, serialization and automatic schema generation, it's needed to add decorators in many places. So, it becomes quite verbose.

It can't handle nested models very well. So, if the JSON body in the request is a JSON object that has inner fields that in turn are nested JSON objects, it cannot be properly documented...

...
```

#### What is OpenAPI for

The OpenAPI schema is what powers the two interactive documentation systems included.

And there are dozens of alternatives, all based on OpenAPI. You could easily add any of those alternatives to your application built with **FastAPI**.

You could also use it to generate code automatically, for clients that communicate with your API. For example, frontend, mobile or IoT applications.

* 🌐 Add Bengali translations for `docs/bn/docs/python-types.md`. PR [#11376](https://github.com/tiangolo/fastapi/pull/11376) by [@imtiaz101325](https://github.com/imtiaz101325).
* 🌐 Add Korean translation for `docs/ko/docs/tutorial/security/simple-oauth2.md`. PR [#5744](https://github.com/tiangolo/fastapi/pull/5744) by [@KdHyeon0661](https://github.com/KdHyeon0661).

    ...
```

...the prefix must not include a final `/`.

So, the prefix in this case is `/items`.

We can also add a list of `tags` and extra `responses` that will be applied to all the *path operations* included in this router.

And we can add a list of `dependencies` that will be added to all the *path operations* in the router and will be executed/solved for each request made to them.

!!! tip

---

Например, в Visual Studio Code вы можете выполнить следующие шаги:

* Перейдите на панель "Debug".
* Выберите "Add configuration...".
* Выберите "Python"
* Запустите отладчик "`Python: Current File (Integrated Terminal)`".

Это запустит сервер с вашим **FastAPI** кодом, остановится на точках останова, и т.д.