### 拡張版 **FastAPI** アプリファイル

**FastAPI** アプリに `main_b.py` ファイルがあるとします。

そのファイルには、エラーを返す可能性のある `GET` オペレーションがあります。

また、いくつかのエラーを返す可能性のある `POST` オペレーションもあります。

これらの *path operation* には `X-Token` ヘッダーが必要です。

{* ../../docs_src/app_testing/app_b_py310/main.py *}

### 拡張版テストファイル

次に、先程のものに拡張版のテストを加えた、`test_main_b.py` を作成します。

{* ../../docs_src/app_testing/app_b/test_main.py *}

	AmzExpires              = "X-Amz-Expires"
	AmzSignedHeaders        = "X-Amz-SignedHeaders"
	AmzSignature            = "X-Amz-Signature"
	AmzCredential           = "X-Amz-Credential"
	AmzSecurityToken        = "X-Amz-Security-Token"
	AmzDecodedContentLength = "X-Amz-Decoded-Content-Length"
	AmzTrailer              = "X-Amz-Trailer"
	AmzMaxParts             = "X-Amz-Max-Parts"
	AmzPartNumberMarker     = "X-Amz-Part-Number-Marker"

│   ├── main.py
│   └── test_main.py
```

이제 **FastAPI** 앱이 있는 `main.py` 파일에 몇 가지 다른 **경로 작업** 이 추가된 경우를 생각해봅시다.

단일 오류를 반환할 수 있는 `GET` 작업이 있습니다.

여러 다른 오류를 반환할 수 있는 `POST` 작업이 있습니다.

두 *경로 작업* 모두 `X-Token` 헤더를 요구합니다.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python

我们将在主 `FastAPI` 应用中包含该 `APIRouter`，但首先，让我们来看看依赖项和另一个 `APIRouter`。

## 依赖项

我们了解到我们将需要一些在应用程序的好几个地方所使用的依赖项。

因此，我们将它们放在它们自己的 `dependencies` 模块（`app/dependencies.py`）中。

现在我们将使用一个简单的依赖项来读取一个自定义的 `X-Token` 请求首部：

```Python hl_lines="1  4-6" title="app/dependencies.py"
{!../../docs_src/bigger_applications/app/dependencies.py!}
```

/// tip

我们正在使用虚构的请求首部来简化此示例。

   * the same way.
   */
  public CharSource asCharSource(Charset charset) {
    return new AsCharSource(charset);
  }

  /**
   * Opens a new {@link InputStream} for reading from this source. This method returns a new,
   * independent stream each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned stream is closed.
   *

 *
 * <p>A high-quality hash function strives for some subset of the following virtues:
 *
 * <ul>
 *   <li><b>collision-resistant:</b> while the definition above requires making at least <i>some</i>
 *       token attempt, one measure of the quality of a hash function is <i>how well</i> it succeeds
 *       at this goal. Important note: it may be easy to achieve the theoretical minimum collision

 *
 * <p>A high-quality hash function strives for some subset of the following virtues:
 *
 * <ul>
 *   <li><b>collision-resistant:</b> while the definition above requires making at least <i>some</i>
 *       token attempt, one measure of the quality of a hash function is <i>how well</i> it succeeds
 *       at this goal. Important note: it may be easy to achieve the theoretical minimum collision

			Key:   target.NATSUserCredentials,
			Value: cfg.UserCredentials,
		},
		config.KV{
			Key:   target.NATSPassword,
			Value: cfg.Password,
		},
		config.KV{
			Key:   target.NATSToken,
			Value: cfg.Token,
		},
		config.KV{
			Key:   target.NATSNKeySeed,
			Value: cfg.NKeySeed,
		},
		config.KV{
			Key:   target.NATSCertAuthority,
			Value: cfg.CertAuthority,
		},
		config.KV{

func parsePAXRecord(s string) (k, v, r string, err error) {
	// The size field ends at the first space.
	nStr, rest, ok := strings.Cut(s, " ")
	if !ok {
		return "", "", s, ErrHeader
	}

	// Parse the first token as a decimal integer.
	n, perr := strconv.ParseInt(nStr, 10, 0) // Intentionally parse as native int
	if perr != nil || n < 5 || n > int64(len(s)) {
		return "", "", s, ErrHeader
	}

...
```

#### What is OpenAPI for { #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**.