1pub fn add_one(left: u64) -> u64 { 2 left + 1 3} 4 5#[cfg(test)] 6mod tests { 7 use super::*; 8 9 #[test] 10 fn it_works() { 11 let result = add_one(2); 12 assert_eq!(result, 3); 13 } 14}