1 #[no_mangle] my_favorite_number() -> i322 pub extern "C" fn my_favorite_number() -> i32 { 3 4 4 } 5 6 #[cfg(test)] 7 mod tests { 8 use super::*; 9 10 #[test] test_my_favorite_number()11 fn test_my_favorite_number() { 12 assert_eq!(4, my_favorite_number()); 13 } 14 } 15