E.g. `pip install httpx`.

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.

                }
            )
            kwargs["pattern"] = pattern or regex
        else:
            kwargs["regex"] = pattern or regex
            kwargs.update(**current_json_schema_extra)
        use_kwargs = {k: v for k, v in kwargs.items() if v is not _Unset}

        super().__init__(**use_kwargs)

    def __repr__(self) -> str:

            annotation=type_, default=default, alias=alias
        )
    else:
        field_info = field_info or FieldInfo()
    kwargs = {"name": name, "field_info": field_info}
    if PYDANTIC_V2:
        kwargs.update({"mode": mode})
    else:
        kwargs.update(
            {
                "type_": type_,
                "class_validators": class_validators,
                "default": default,

It is designed to have functions that receive two parameters, one "request" and one "response". Then you "read" parts from the request, and "write" parts to the response. Because of this design, it is not possible to declare request parameters and bodies with standard Python type hints as function parameters.

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

## Details

The first `"/static"` refers to the sub-path this "sub-application" will be "mounted" on. So, any path that starts with `"/static"` will be handled by it.

The `directory="static"` refers to the name of the directory that contains your static files.

The `name="static"` gives it a name that can be used internally by **FastAPI**.

        Any,
        Doc(
            """
            Include extra fields used by the JSON Schema.
            """
        ),
        deprecated(
            """
            The `extra` kwargs is deprecated. Use `json_schema_extra` instead.
            """
        ),
    ],
) -> Any:
    """
    Declare a path parameter for a *path operation*.

    Read more about it in the

    ```

    Note that for OAuth2 the scope `items:read` is a single scope in an opaque string.
    You could have custom internal logic to separate it by colon caracters (`:`) or
    similar, and get the two parts `items` and `read`. Many applications do that to
    group and organize permissions, you could do it as well in your application, just
    know that that it is application specific, it's not part of the specification.
    """

* Do not change the paths in links to images, code files, Markdown documents.

* However, when a Markdown document is translated, the `#hash-parts` in links to its headings may change. Update these links if possible.
    * Search for such links in the translated document using the regex `#[^# ]`.

class CustomError(Exception):
    pass


@router.websocket("/custom_error/")
async def router_ws_custom_error(websocket: WebSocket):
    raise CustomError()


def make_app(app=None, **kwargs):
    app = app or FastAPI(**kwargs)
    app.include_router(router)
    app.include_router(prefix_router, prefix="/prefix")
    app.include_router(native_prefix_route)
    return app


app = make_app(app)

# Reference - Code API

Here's the reference or code API, the classes, functions, parameters, attributes, and
all the FastAPI parts you can use in your applications.

If you want to **learn FastAPI** you are much better off reading the