Function db_sqlx_postgres::dev::tests::email_register_works

pub async fn email_register_works<T>(
    db: &'_ T, 
    email: &'_ str, 
    username: &'_ str, 
    password: &'_ str, 
    secret: &'_ str, 
    username2: &'_ str
) where
    T: LibAdminDatabase, 

test email registration implementation