# 测试 WebSockets

测试 WebSockets 也使用 `TestClient`。

为此，要在 `with` 语句中使用 `TestClient` 连接 WebSocket。

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note | 笔记

更多细节详见 <a href="https://www.starlette.dev/testclient/#testing-websocket-sessions" class="external-link" target="_blank">Starlette 官档 - 测试 WebSockets</a>。

participant handler as Exception handler
participant dep as Dep with yield
participant operation as Path Operation
participant tasks as Background tasks

    Note over client,operation: Can raise exceptions, including HTTPException
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise Exception
        dep -->> handler: Raise Exception
        handler -->> client: HTTP error response
    end

    participant Server as FastAPI Server

    Client->>Proxy: HTTPS Request<br/>Host: mysuperapp.com<br/>Path: /items

    Note over Proxy: Proxy adds forwarded headers

    Proxy->>Server: HTTP Request<br/>X-Forwarded-For: [client IP]<br/>X-Forwarded-Proto: https<br/>X-Forwarded-Host: mysuperapp.com<br/>Path: /items

    Note over Server: Server interprets headers<br/>(if --forwarded-allow-ips is set)

	{"BETWEEN_256_KB_AND_512_KB", 256 * humanize.KiByte, 512*humanize.KiByte - 1}, // not exported, for support use only
	{"BETWEEN_512_KB_AND_1_MB", 512 * humanize.KiByte, humanize.MiByte - 1},       // not exported, for support use only
	{"BETWEEN_1024B_AND_1_MB", humanize.KiByte, humanize.MiByte - 1},
	{"BETWEEN_1_MB_AND_10_MB", humanize.MiByte, humanize.MiByte*10 - 1},

{* ../../docs_src/app_testing/tutorial001_py39.py hl[2,12,15:18] *}

/// tip

Notice that the testing functions are normal `def`, not `async def`.

And the calls to the client are also normal calls, not using `await`.

This allows you to use `pytest` directly without complications.

///

/// note | Technical Details

You could also use `from starlette.testclient import TestClient`.

<span style="color: green;">INFO</span>:     Waiting for application startup.
<span style="color: green;">INFO</span>:     Application startup complete.
```

</div>

/// note

La commande `uvicorn main:app` fait référence à :

* `main` : le fichier `main.py` (le module Python).
* `app` : l'objet créé dans `main.py` via la ligne `app = FastAPI()`.

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

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

{* ../../docs_src/app_testing/tutorial002_py39.py hl[27:31] *}

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.dev/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

代替：

```Python
q: Union[str, None] = None
```

但是现在我们正在用 `Query` 声明它，例如：

```Python
q: Union[str, None] = Query(default=None, min_length=3)
```

因此，当你在使用 `Query` 且需要声明一个值是必需的时，只需不声明默认参数：

{* ../../docs_src/query_params_str_validations/tutorial006.py hl[7] *}

### 使用`None`声明必需参数

你可以声明一个参数可以接收`None`值，但它仍然是必需的。这将强制客户端发送一个值，即使该值是`None`。

为此，你可以声明`None`是一个有效的类型，并仍然使用`default=...`：

/**
 * Holds data relevant for an execution event.
 *
 */
public interface ExecutionEvent {

    /**
     * The possible types of execution events.
     *
     * Note: do not modify this enum, or, make sure that this enum and
     * {@link org.apache.maven.api.EventType} have same elements in same order.
     */
    enum Type {
        ProjectDiscoveryStarted,
        SessionStarted,

import org.apache.maven.lifecycle.LifecycleExecutionException;

/**
 * <p>
 * Extension point that allows build extensions observe and possibly veto project build execution.
 * </p>
 * <strong>Note:</strong> This interface is part of work in progress and can be changed or removed without notice.
 *
 * @see ExecutionListener
 * @see MojoExecutionListener
 * @since 3.1.2
 */
public interface ProjectExecutionListener {