#[cfg(test)]
mod examples {
    use day65::isbn_validator;

    #[test]
    fn example1() {
        assert!(isbn_validator("0747532699").unwrap());
    }

    #[test]
    fn example2() {
        assert!(isbn_validator("123456789X").unwrap());
    }

    #[test]
    fn example3() {
        assert!(!isbn_validator("1234567890").unwrap());
    }

    #[test]
    fn example4() {
        assert_eq!(
            isbn_validator("abcdefghil"),
            Err("Only digits allowed".to_owned())
        )
    }

    #[test]
    fn example5() {
        assert_eq!(
            isbn_validator("123"),
            Err("Invalid length for the ISBN".to_owned())
        )
    }
}