Files
100-exercises-to-learn-rust/helpers/ticket_fields/src/title.rs

73 lines
1.8 KiB
Rust

use std::convert::TryFrom;
#[derive(Debug, PartialEq, Clone, Eq)]
pub struct TicketTitle(String);
#[derive(Debug, thiserror::Error)]
pub enum TicketTitleError {
#[error("The title cannot be empty")]
Empty,
#[error("The title cannot be longer than 50 bytes")]
TooLong,
}
impl TryFrom<String> for TicketTitle {
type Error = TicketTitleError;
fn try_from(value: String) -> Result<Self, Self::Error> {
validate(&value)?;
Ok(Self(value))
}
}
impl TryFrom<&str> for TicketTitle {
type Error = TicketTitleError;
fn try_from(value: &str) -> Result<Self, Self::Error> {
validate(value)?;
Ok(Self(value.to_string()))
}
}
fn validate(title: &str) -> Result<(), TicketTitleError> {
if title.is_empty() {
Err(TicketTitleError::Empty)
} else if title.len() > 50 {
Err(TicketTitleError::TooLong)
} else {
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use common::{overly_long_title, valid_title};
use std::convert::TryFrom;
#[test]
fn test_try_from_string() {
let input = valid_title();
let title = TicketTitle::try_from(input.clone()).unwrap();
assert_eq!(title.0, input);
}
#[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 err = TicketTitle::try_from(overly_long_title()).unwrap_err();
assert_eq!(err.to_string(), "The title cannot be longer than 50 bytes");
}
#[test]
fn test_try_from_str() {
let title = TicketTitle::try_from("A title").unwrap();
assert_eq!(title.0, "A title");
}
}