This doesn't affect `Path` parameters as the value is always required.
            The parameter is available only for compatibility.
            """
        ),
    ] = _Unset,
    alias: Annotated[
        Optional[str],
        Doc(
            """
            An alternative name for the parameter field.

            This will be used to extract the data and for the generated OpenAPI.

    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/api_route": {
                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",

    client = TestClient(app)
    response = client.get("/openapi.json")
    data = response.json()
    assert data == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/": {
                "post": {
                    "summary": "Post Root",
                    "operationId": "foo_post_root",
                    "requestBody": {
                        "content": {