1pub fn add(left: u64, right: u64) -> u64 { 2 left + right 3} 4#[cfg(test)] 5mod tests { 6 use super::*; 7 8 #[test] 9 fn it_works() { 10 let result = add(2, 2); 11 assert_eq!(result, 4); 12 } 13}