1mod handler;2pub use handler::{Handler, PlainHandler, NoopHandler, NixHandler, ClonableHandler};34pub fn add(left: usize, right: usize) -> usize {5 left + right6}78#[cfg(test)]9mod tests {10 use super::*;1112 #[test]13 fn it_works() {14 let result = add(2, 2);15 assert_eq!(result, 4);16 }17}