This tutorial shows you how to use **FastAPI** with most of its features, step by step.

Each section gradually builds on the previous ones, but it's structured to separate topics, so that you can go directly to any specific one to solve your specific API needs.

It is also built to work as a future reference so you can come back and see exactly what you need.

## Run the code { #run-the-code }

Connections
===========

Although you provide only the URL, OkHttp plans its connection to your webserver using three types: URL, Address, and Route.

### [URLs](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-http-url/)

URLs (like `https://github.com/square/okhttp`) are fundamental to HTTP and the Internet. In addition to being a universal, decentralized naming scheme for everything on the web, they also specify how to access web resources.

    echo "Please install either command, or disable validation by removing 'distributionSha256Sum' from your maven-wrapper.properties." >&2
    exit 1
  fi
  if [ $distributionSha256Result = false ]; then
    echo "Error: Failed to validate Maven distribution SHA-256, your Maven distribution might be compromised." >&2
    echo "If you updated your Maven version, you need to update the specified distributionSha256Sum property." >&2
    exit 1
  fi

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

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## Separating tests { #separating-tests }

In a real application, you probably would have your tests in a different file.

## L'ordre importe

Quand vous créez des *fonctions de chemins*, vous pouvez vous retrouver dans une situation où vous avez un chemin fixe.

Tel que `/users/me`, disons pour récupérer les données sur l'utilisateur actuel.

Et vous avez un second chemin : `/users/{user_id}` pour récupérer de la donnée sur un utilisateur spécifique grâce à son identifiant d'utilisateur

### Tested { #tested }

* 100% <abbr title="The amount of code that is automatically tested">test coverage</abbr>.
* 100% <abbr title="Python type annotations, with this your editor and external tools can give you better support">type annotated</abbr> code base.

### Motivation

This library makes it easy to test that your app Does The Right Thing when it
makes HTTP and HTTPS calls. It lets you specify which responses to return and
then verify that requests were made as expected.

Because it exercises your full HTTP stack, you can be confident that you're
testing everything. You can even copy & paste HTTP responses from your real web

For example, you can declare a response with a status code `404` that uses a Pydantic model and has a custom `description`.

And a response with a status code `200` that uses your `response_model`, but includes a custom `example`:

{* ../../docs_src/additional_responses/tutorial003.py hl[20:31] *}

It will all be combined and included in your OpenAPI, and shown in the API docs:

Mais c'est beaucoup plus complexe que cela.

/// tip

Si vous êtes pressé ou si cela ne vous intéresse pas, passez aux sections suivantes pour obtenir des instructions étape par étape afin de tout configurer avec différentes techniques.

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Pour apprendre les bases du HTTPS, du point de vue d'un utilisateur, consultez <a href="https://howhttps.works/"
class="external-link" target="_blank">https://howhttps.works/</a>.

/// tip

Some editors check for unused function parameters, and show them as errors.

Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors.

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

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