This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details

```Python hl_lines="1  15"
{!../../../docs_src/debugging/tutorial001.py!}
```

### À propos de `__name__ == "__main__"`

Le but principal de `__name__ == "__main__"` est d'avoir du code qui est exécuté lorsque votre fichier est appelé avec :

<div class="termy">

```console
$ python myapp.py
```

</div>

mais qui n'est pas appelé lorsqu'un autre fichier l'importe, comme dans :

```Python
from myapp import app
```

            ]
        }
    )


def test_main_depends_q_foo():
    response = client.get("/main-depends/?q=foo")
    assert response.status_code == 200
    assert response.json() == {
        "in": "main-depends",
        "params": {"q": "foo", "skip": 0, "limit": 100},
    }


def test_main_depends_q_foo_skip_100_limit_200():
    response = client.get("/main-depends/?q=foo&skip=100&limit=200")

### Providing the `root_path`

To achieve this, you can use the command line option `--root-path` like:

<div class="termy">

```console
$ fastapi run main.py --root-path /api/v1

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

If you use Hypercorn, it also has the option `--root-path`.

## The main `FastAPI`

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI`

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

Die Datei `main.py` hätte als Inhalt:

```Python
{!../../../docs_src/async_tests/main.py!}
```

Die Datei `test_main.py` hätte die Tests für `main.py`, das könnte jetzt so aussehen:

```Python
{!../../../docs_src/async_tests/test_main.py!}
```

## Es ausführen

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

📁 `main.py` 🔜 ✔️:

```Python
{!../../../docs_src/async_tests/main.py!}
```

📁 `test_main.py` 🔜 ✔️ 💯 `main.py`, ⚫️ 💪 👀 💖 👉 🔜:

```Python
{!../../../docs_src/async_tests/test_main.py!}
```

## 🏃 ⚫️

👆 💪 🏃 👆 💯 🐌 📨:

<div class="termy">

```console

    from docs_src.settings.app02 import main

    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    settings = main.get_settings()
    assert settings.app_name == "Awesome API"
    assert settings.items_per_user == 50


@needs_pydanticv2
def test_override_settings():
    from docs_src.settings.app02 import test_main

## 🗄 ➕

🕐❔ 👆 📣 *➡ 🛠️* 👆 🈸, **FastAPI** 🔁 🏗 🔗 🗃 🔃 👈 *➡ 🛠️* 🔌 🗄 🔗.

!!! note "📡 ℹ"
    🗄 🔧 ⚫️ 🤙 <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#operation-object" class="external-link" target="_blank">🛠️ 🎚</a>.

⚫️ ✔️ 🌐 ℹ 🔃 *➡ 🛠️* &amp; ⚙️ 🏗 🏧 🧾.

⚫️ 🔌 `tags`, `parameters`, `requestBody`, `responses`, ♒️.

В вашем FastAPI приложении, импортируйте и вызовите `uvicorn` напрямую:

```Python hl_lines="1  15"
{!../../../docs_src/debugging/tutorial001.py!}
```

### Описание `__name__ == "__main__"`

Главная цель использования `__name__ == "__main__"` в том, чтобы код выполнялся при запуске файла с помощью:

<div class="termy">

```console
$ python myapp.py
```

</div>