100-exercises-to-learn-rust/exercises/05_ticket_v2/15_outro/src/title.rs

// TODO: Implement `TryFrom<String>` and `TryFrom<&str>` for the `TicketTitle` type,
//   enforcing that the title is not empty and is not longer than 50 characters.
//   Implement the traits required to make the tests pass too.

pub struct TicketTitle(String);

#[cfg(test)]
mod tests {
    use super::*;
    use std::convert::TryFrom;

    #[test]
    fn test_try_from_string() {
        let title = TicketTitle::try_from("A title".to_string()).unwrap();
        assert_eq!(title.0, "A title");
    }

    #[test]
    fn test_try_from_empty_string() {
        let err = TicketTitle::try_from("".to_string()).unwrap_err();
        assert_eq!(err.to_string(), "The title cannot be empty");
    }

    #[test]
    fn test_try_from_long_string() {
        let title =
            "A title that's definitely longer than what should be allowed in a development ticket"
                .to_string();
        let err = TicketTitle::try_from(title).unwrap_err();
        assert_eq!(
            err.to_string(),
            "The title cannot be longer than 50 characters"
        );
    }

    #[test]
    fn test_try_from_str() {
        let title = TicketTitle::try_from("A title").unwrap();
        assert_eq!(title.0, "A title");
    }
}