Stuck with pavex getting started exercise

snippets.md

user_agent.rs

use pavex::http::header::{ToStrError, USER_AGENT};
use pavex::request::RequestHead;
use pavex::response::Response;

pub enum UserAgent {
	Unknown,
	Known(String),
}

impl UserAgent {
    pub fn extract(request_head: &RequestHead) -> Result<Self, ToStrError > {
        let Some(user_agent) = request_head.headers.get(USER_AGENT) else {
            return Ok(UserAgent::Unknown);
        };

        user_agent.to_str().map(|s| UserAgent::Known(s.into()))
    }
}

pub fn invalid_user_agent(_e: &ToStrError) -> Response {
    Response::bad_request()
        .set_typed_body("The `User-Agent` header value must be a valid UTF-8 string")
}

blueprint.rs

pub fn blueprint() -> Blueprint {
    let mut bp = Blueprint::new();
    register_common_constructors(&mut bp);

    add_telemetry_middleware(&mut bp);

    bp.constructor(
        f!(crate::user_agent::UserAgent::extract),
        Lifecycle::RequestScoped,
    )
    .error_handler(f!(crate::user_agent::invalid_user_agent));

    bp.route(GET, "/api/ping", f!(crate::routes::status::ping));
    bp.route(
        GET,
        "/api/greet/:name",
        f!(crate::routes::greet::greet),
    );
    bp
}

test

#[tokio::test]
async fn non_utf8_user_agent_is_rejected() {
    let api = TestApi::spawn().await;
    let name = "Ursula";

    let response = api
        .api_client
        .get(&format!("{}/api/greet/{name}", &api.api_address))
        .header("User-Agent", b"hello\xfa".as_slice())
        .send()
        .await
        .expect("Failed to execute request.");

    assert_eq!(response.status().as_u16(), StatusCode::BAD_REQUEST.as_u16());
    assert_eq!(
        response.text().await.unwrap(),
        "The `User-Agent` header value must be a valid UTF-8 string"
    );
}