@needs_py310
@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"User-Agent": "testclient"}),
        ("/items", {"X-Header": "notvalid"}, 200, {"User-Agent": "testclient"}),
        ("/items", {"User-Agent": "FastAPI test"}, 200, {"User-Agent": "FastAPI test"}),
    ],
)
def test(path, headers, expected_status, expected_response, client: TestClient):

Таким образом вы можете использовать `user_agent`, как обычно, в коде Python, вместо того, чтобы вводить заглавные буквы как `User_Agent` или что-то подобное.

Если по какой-либо причине вам необходимо отключить автоматическое преобразование подчеркиваний в дефисы, установите для параметра `convert_underscores` в `Header` значение `False`:

=== "Python 3.10+"

## 自动转换

`Header` 比 `Path`、`Query` 和 `Cookie` 提供了更多功能。

大部分标准请求头用**连字符**分隔，即**减号**（`-`）。

但是 `user-agent` 这样的变量在 Python 中是无效的。

因此，默认情况下，`Header` 把参数名中的字符由下划线（`_`）改为连字符（`-`）来提取并存档请求头 。

同时，HTTP 的请求头不区分大小写，可以使用 Python 标准样式（即 **snake_case**）进行声明。

因此，可以像在 Python 代码中一样使用 `user_agent` ，无需把首字母大写为 `User_Agent` 等形式。

如需禁用下划线自动转换为连字符，可以把 `Header` 的 `convert_underscores` 参数设置为 `False`：

=== "Python 3.10+"

### Refactors

* ♻ Remove `media_type` from `ORJSONResponse` as it's inherited from the parent class. PR [#5805](https://github.com/tiangolo/fastapi/pull/5805) by [@Kludex](https://github.com/Kludex).

    # Language names sourced from https://quickref.me/iso-639-1
    # Contributors may wish to update or change these, e.g. to fix capitalization.
    language_names_path = Path(__file__).parent / "../docs/language_names.yml"
    local_language_names: Dict[str, str] = mkdocs.utils.yaml_load(
        language_names_path.read_text(encoding="utf-8")
    )
    for lang_path in get_lang_paths():

```console
$ uvicorn main:app --host 0.0.0.0 --port 8080 --workers 4
<font color="#A6E22E">INFO</font>:     Uvicorn running on <b>http://0.0.0.0:8080</b> (Press CTRL+C to quit)
<font color="#A6E22E">INFO</font>:     Started parent process [<font color="#A1EFE4"><b>27365</b></font>]
<font color="#A6E22E">INFO</font>:     Started server process [<font color="#A1EFE4">27368</font>]
<font color="#A6E22E">INFO</font>:     Waiting for application startup.

@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"User-Agent": "testclient"}),
        ("/items", {"X-Header": "notvalid"}, 200, {"User-Agent": "testclient"}),
        ("/items", {"User-Agent": "FastAPI test"}, 200, {"User-Agent": "FastAPI test"}),
    ],
)
def test(path, headers, expected_status, expected_response):
    response = client.get(path, headers=headers)

Portanto, você pode usar `user_agent` como faria normalmente no código Python, em vez de precisar colocar as primeiras letras em maiúsculas como `User_Agent` ou algo semelhante.

Se por algum motivo você precisar desabilitar a conversão automática de sublinhados para hífens, defina o parâmetro `convert_underscores` de `Header` para `False`:

But a variable like `user-agent` is invalid in Python.

So, by default, `Header` will convert the parameter names characters from underscore (`_`) to hyphen (`-`) to extract and document the headers.

Also, HTTP headers are case-insensitive, so, you can declare them with standard Python style (also known as "snake_case").