Rust Programming Cookbook

How to do it...

Since we are exploring a built-in library feature, we'll create several tests that cover everything:

1. Create a new project using cargo new not-null --lib and open the project folder using Visual Studio code.
2. To start off, let's see what unwrap() does and replace the default test in src/lib.rs with the following code:

    #[test]    #[should_panic]    fn option_unwrap() {        // Options to unwrap Options        assert_eq!(Some(10).unwrap(), 10);        assert_eq!(None.unwrap_or(10), 10);        assert_eq!(None.unwrap_or_else(|| 5 * 2), 10);                Option::<i32>::None.unwrap();        Option::<i32>::None.expect("Better say something when         panicking");    }

3. Option also wraps values well, and it's sometimes complicated (or simply verbose) to get them out. Here are a number ...