///

## 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`

```Python hl_lines="1  3  7" title="app/main.py"
{!../../docs_src/bigger_applications/app/main.py!}
```

### 🗄 `APIRouter`

🔜 👥 🗄 🎏 🔁 👈 ✔️ `APIRouter`Ⓜ:

```Python hl_lines="5" title="app/main.py"
{!../../docs_src/bigger_applications/app/main.py!}
```

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

在 `main.py` 文件中你有一个 **FastAPI** app:


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

### 测试文件

然后你会有一个包含测试的文件 `test_main.py` 。app可以像Python包那样存在（一样是目录，但有个 `__init__.py` 文件）：

``` hl_lines="5"
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

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

In der Datei `main.py` haben Sie Ihre **FastAPI**-Anwendung:


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

### Testdatei

    [
        (
            "/main-depends/",
            200,
            {"in": "main-depends", "params": {"q": None, "skip": 5, "limit": 10}},
        ),
        (
            "/main-depends/?q=foo",
            200,
            {"in": "main-depends", "params": {"q": "foo", "skip": 5, "limit": 10}},
        ),
        (
            "/main-depends/?q=foo&skip=100&limit=200",
            200,

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

Здесь файл `main.py` является "точкой входа" в Ваше приложение и содержит инициализацию Вашего приложения **FastAPI**:


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

### Файл тестов

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

📁 `main.py` 👆 ✔️ 👆 **FastAPI** 📱:


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

### 🔬 📁

⤴️ 👆 💪 ✔️ 📁 `test_main.py` ⏮️ 👆 💯. ⚫️ 💪 🖖 🔛 🎏 🐍 📦 (🎏 📁 ⏮️ `__init__.py` 📁):

``` hl_lines="5"
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

    #     (NotRequired - Default Java:'src/main/java' & 'src/main/resources' CSharp:'source')
    #   o sql2EntityOutputDirectory: source output directory from as a relative path from the application directory
    #     (NotRequired - Default Java:'src/main/java' CSharp:'source')
    #
    #; applicationOutsideSqlMap = map:{
    #    ; ../../app1 = map:{
    #        ; sqlDirectory = src/main/resources

private fun mainFiles(): List<File> {
  val directories =
    listOf(
      "$prefix/samples/guide/src/main/java/okhttp3/guide",
      "$prefix/samples/guide/src/main/java/okhttp3/recipes",
      "$prefix/samples/guide/src/main/java/okhttp3/recipes/kt",
    ).map { File(it) }

  return directories.flatMap {
    it.listFiles().orEmpty().filter { f -> f.isFile }.toList()
  }
}

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

No arquivo `main.py` você tem seu aplicativo **FastAPI**:


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

### Arquivo de teste