test.rs

pub fn sign_up((form, state): (Json<In<SignupUser>>, State<AppState>)) -> impl Future<Item = HttpResponse, Error = Error> {
    let signup_user = form.into_inner().user;

    let password = hasher().hash(&signup_user.password).unwrap();

    let new_user = NewUser {
        username: signup_user.username.clone(),
        email: signup_user.email.clone(),
        password,
        bio: None,
        image: None,
    };
    
    let db = state.db.clone();

    futures::future::result(signup_user.validate())
        .map_error(|error| map to your error type?)
        .and_then(|_| db.send(new_user).from_err())
        .and_then(|res| match res {
            Ok(user) => Ok(HttpResponse::Ok().json(UserResponse::from(user))),
            Err(e) => Ok(e.error_response()),
        })
}