available, instead of erroring out, the dependency result will be
                `None`.

                This is useful when you want to have optional authentication.

                It is also useful when you want to have authentication that can be
                provided in one of multiple optional ways (for example, in a query
                parameter or in an HTTP Bearer token).
                """
            ),

    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"
    assert response.json() == {"detail": "Invalid authentication credentials"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"

    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"
    assert response.json() == {"detail": "Invalid authentication credentials"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"

    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == 'Basic realm="simple"'
    assert response.json() == {"detail": "Invalid authentication credentials"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"

    * A cookie.
* `http`: standard HTTP authentication systems, including:
    * `bearer`: a header `Authorization` with a value of `Bearer ` plus a token. This is inherited from OAuth2.
    * HTTP Basic authentication.
    * HTTP Digest, etc.
* `oauth2`: all the OAuth2 ways to handle security (called "flows").
    * Several of these flows are appropriate for building an OAuth 2.0 authentication provider (like Google, Facebook, Twitter, GitHub, etc):

    If you integrate your API with an OAuth2 provider, you will be able to authenticate and come back to the API docs with the acquired credentials. And interact with it using the real OAuth2 authentication.

    Swagger UI will handle it behind the scenes for you, but it needs this "redirect" helper.

### Create a *path operation* to test it

Now, to be able to test that everything works, create a *path operation*:

### Use cases: external service

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

  - author: Nils de Bruin
    author_link: https://medium.com/@nilsdebruin
    link: https://medium.com/data-rebels/fastapi-authentication-revisited-enabling-api-key-authentication-122dc5975680
    title: 'FastAPI authentication revisited: Enabling API key authentication'
  - author: Nick Cortale
    author_link: https://nickc1.github.io/
    link: https://nickc1.github.io/api,/scikit-learn/2019/01/10/scikit-fastapi.html

    * Einem Cookie.
* `http`: Standard-HTTP-Authentifizierungssysteme, einschließlich:
    * `bearer`: ein Header `Authorization` mit dem Wert `Bearer` plus einem Token. Dies wird von OAuth2 geerbt.
    * HTTP Basic Authentication.
    * HTTP Digest, usw.
* `oauth2`: Alle OAuth2-Methoden zum Umgang mit Sicherheit (genannt „Flows“).

                be `None`.

                This is useful when you want to have optional authentication.

                It is also useful when you want to have authentication that can be
                provided in one of multiple optional ways (for example, with OpenID
                Connect or in a cookie).
                """
            ),
        ] = True,
    ):
        self.model = OpenIdConnectModel(