// options2.rs // // Execute `rustlings hint options2` or use the `hint` watch subcommand for a // hint. #[cfg(test)] mod tests { #[test] fn simple_option() { let target = "rustlings"; let optional_target = Some(target); // TODO: Make this an if let statement whose value is "Some" type if let Some(word) = optional_target { assert_eq!(word, target); } } #[test] fn layered_option() { let range = 10; let mut optional_integers: Vec> = vec![None]; for i in 1..(range + 1) { optional_integers.push(Some(i)); } let mut cursor = range; // TODO: make this a while let statement - remember that vector.pop also // adds another layer of Option. You can stack `Option`s into // while let and if let. while let Some(int) = optional_integers.pop() { if let Some(integer) = int { assert_eq!(integer, cursor); cursor -= 1; } } assert_eq!(cursor, 0); } }