* custom builds of OkHttp please include a qualifier your version name, like "4.7.0-mycompany.3".
   * The version string is configured in the root project's `build.gradle`.
   *
   * Note that OkHttp's runtime version may be different from the version specified in your
   * project's build file due to the dependency resolution features of your build tool.
   *
   * [semver]: https://semver.org
   */

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:

/// tip

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.

///

## Separating tests

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

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.

///

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>.

  }

  /**
   * Returns the empty immutable list. This list behaves and performs comparably to {@link
   * Collections#emptyList}, and is preferable mainly for consistency and maintainability of your
   * code.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting to any type is safe because the list will never hold any elements.
  @SuppressWarnings("unchecked")

package gorm

import "time"

// Model a basic GoLang struct which includes the following fields: ID, CreatedAt, UpdatedAt, DeletedAt
// It may be embedded into your model or you may build your own model without it
//
//	type User struct {
//	  gorm.Model
//	}
type Model struct {
	ID        uint `gorm:"primarykey"`
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt DeletedAt `gorm:"index"`

# Templates

You can use any template engine you want with **FastAPI**.

A common choice is Jinja2, the same one used by Flask and other tools.

There are utilities to configure it easily that you can use directly in your **FastAPI** application (provided by Starlette).

## Install dependencies

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and install `jinja2`:

<div class="termy">

The same example from above, returning an `HTMLResponse`, could look like:

```Python hl_lines="2  7  19"
{!../../docs_src/custom_response/tutorial003.py!}
```

/// warning

                                            {
                                                "name": "Baz",
                                                "price": "thirty five point four",
                                            },
                                        ],
                                    }
                                )
                                | IsDict(

One particular advantage that is not necessarily obvious is that you can **generate clients** (sometimes called <abbr title="Software Development Kits">**SDKs**</abbr> ) for your API, for many different **programming languages**.

## OpenAPI Client Generators

There are many tools to generate clients from **OpenAPI**.