Beginnen wir mit einem Beispiel und sehen es uns dann im Detail an.

Wir erstellen eine asynchrone Funktion `lifespan()` mit `yield` wie folgt:

```Python hl_lines="16  19"
{!../../docs_src/events/tutorial003.py!}
```

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_py310/main.py!}
```

////

//// tab | Python 3.6+

```Python
{!> ../../docs_src/app_testing/app_b/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。

```Python
{!> ../../docs_src/app_testing/app_b/test_main.py!}
```

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an.py!}
```

////

//// tab | Python 3.8 Annotated가 없는 경우

/// tip | "팁"

가능하다면 `Annotated`가 달린 버전을 권장합니다.

///

```Python hl_lines="15"
{!> ../../docs_src/dependencies/tutorial012.py!}
```

////

## Pydantic Models for Input and Output

Let's say you have a Pydantic model with default values, like this one:

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py ln[1:7] hl[7] *}

### Model for Input

If you use this model as an input like here:

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py ln[1:15] hl[14] *}

import pytest
from fastapi.exceptions import FastAPIError
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008c_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")

```Python hl_lines="7"
{!../../docs_src/first_steps/tutorial003.py!}
```

/// note | "Hinweis"

Wenn Sie den Unterschied nicht kennen, lesen Sie [Async: *„In Eile?“*](../async.md#in-eile){.internal-link target=_blank}.

///

### Schritt 5: den Inhalt zurückgeben

```Python hl_lines="8"
{!../../docs_src/first_steps/tutorial001.py!}
```

///

## 動機

簡単な例から始めてみましょう:

```Python
{!../../docs_src/python_types/tutorial001.py!}
```

このプログラムを実行すると以下が出力されます:

```
John Doe
```

この関数は以下のようなことを行います:

* `first_name`と`last_name`を取得します。
* `title()`を用いて、それぞれの最初の文字を大文字に変換します。
* 真ん中にスペースを入れて<abbr title="次から次へと中身を入れて一つにまとめる">連結</abbr>します。

```Python hl_lines="2"
{!../../docs_src/python_types/tutorial001.py!}
```

### 編集

Vamos ver o exemplo anterior novamente:

```Python hl_lines="6"
{!../../docs_src/response_status_code/tutorial001.py!}
```

`201` é o código de status para "Criado".

Mas você não precisa memorizar o que cada um desses códigos significa.

Você pode usar as variáveis de conveniência de `fastapi.status`.

```Python hl_lines="1  6"
{!../../docs_src/response_status_code/tutorial002.py!}
```

from pathlib import Path

from fastapi.testclient import TestClient

from docs_src.custom_response import tutorial009
from docs_src.custom_response.tutorial009 import app

client = TestClient(app)


def test_get(tmp_path: Path):
    file_path: Path = tmp_path / "large-video-file.mp4"
    tutorial009.some_file_path = str(file_path)
    test_content = b"Fake video bytes"
    file_path.write_bytes(test_content)
    response = client.get("/")

```Python hl_lines="14-19"
{!../../docs_src/events/tutorial003.py!}
```

🥇 🍕 🔢, ⏭ `yield`, 🔜 🛠️ **⏭** 🈸 ▶️.

& 🍕 ⏮️ `yield` 🔜 🛠️ **⏮️** 🈸 ✔️ 🏁.

### 🔁 🔑 👨‍💼

🚥 👆 ✅, 🔢 🎀 ⏮️ `@asynccontextmanager`.

👈 🗜 🔢 🔘 🕳 🤙 "**🔁 🔑 👨‍💼**".

```Python hl_lines="1  13"
{!../../docs_src/events/tutorial003.py!}
```