trpl-zh-cn/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/src/lib.rs

pub struct Guess {
    value: i32,
}

impl Guess {
    pub fn new(value: i32) -> Guess {
        // ANCHOR: here
        if value < 1 {
            panic!(
                "Guess value must be less than or equal to 100, got {}.",
                value
            );
        } else if value > 100 {
            panic!(
                "Guess value must be greater than or equal to 1, got {}.",
                value
            );
        }
        // ANCHOR_END: here

        Guess { value }
    }
}

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

    #[test]
    #[should_panic(expected = "Guess value must be less than or equal to 100")]
    fn greater_than_100() {
        Guess::new(200);
    }
}