After this, the client and the server have an **encrypted TCP connection**, this is what TLS provides. And then they can use that connection to start the actual **HTTP communication**.

And that's what **HTTPS** is, it's just plain **HTTP** inside a **secure TLS connection** instead of a pure (unencrypted) TCP connection.

!!! tip

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

```Python hl_lines="18-20"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

For the **next request**, as we will reset that context variable again in the `async` dependency `reset_db_state()` and then create a new connection in the `get_db()` dependency, that new request will have its own database state (connection, transactions, etc).

!!! tip

<img src="/img/tutorial/websockets/image03.png">

You can send (and receive) many messages:

<img src="/img/tutorial/websockets/image04.png">

And all of them will use the same WebSocket connection.

## Using `Depends` and others

In WebSocket endpoints you can import from `fastapi` and use:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

# Test Client - `TestClient`

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

And it will work and will be useful **during development**.

But if your connection to the server is lost, the **running process** will probably die.

# Histoire, conception et avenir

Il y a quelque temps, <a href="https://github.com/tiangolo/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">un utilisateur de **FastAPI** a demandé</a> :

> Quelle est l'histoire de ce projet ? Il semble être sorti de nulle part et est devenu génial en quelques semaines [...].

Voici un petit bout de cette histoire.

## Alternatives

# Testing WebSockets

You can use the same `TestClient` to test WebSockets.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

```Python hl_lines="27-31"
{!../../../docs_src/app_testing/tutorial002.py!}
```

!!! note

## About versions

Following the Semantic Versioning conventions, any version below `1.0.0` could potentially add breaking changes.

FastAPI also follows the convention that any "PATCH" version change is for bug fixes and non-breaking changes.

!!! tip
    The "PATCH" is the last number, for example, in `0.2.3`, the PATCH version is `3`.

So, you should be able to pin to a version like:

## À propos des versions

Suivant les conventions de versionnage sémantique, toute version inférieure à `1.0.0` peut potentiellement ajouter
des changements non rétrocompatibles.

FastAPI suit également la convention que tout changement de version "PATCH" est pour des corrections de bogues et
des changements rétrocompatibles.

!!! tip "Astuce"
    Le "PATCH" est le dernier chiffre, par exemple, dans `0.2.3`, la version PATCH est `3`.