chay.dev
1use std::cmp::Ordering;
2
3#[derive(PartialEq, Debug)]
4enum CreationError {
5 Negative,
6 Zero,
7}
8
9#[derive(PartialEq, Debug)]
10struct PositiveNonzeroInteger(u64);
11
12impl PositiveNonzeroInteger {
13 fn new(value: i64) -> Result<Self, CreationError> {
14 // TODO: This function shouldn't always return an `Ok`.
15 match value.cmp(&0) {
16 Ordering::Greater => Ok(Self(value as u64)),
17 Ordering::Equal => Err(CreationError::Zero),
18 Ordering::Less => Err(CreationError::Negative),
19 }
20 }
21}
22
23fn main() {
24 // You can optionally experiment here.
25}
26
27#[cfg(test)]
28mod tests {
29 use super::*;
30
31 #[test]
32 fn test_creation() {
33 assert_eq!(
34 PositiveNonzeroInteger::new(10),
35 Ok(PositiveNonzeroInteger(10)),
36 );
37 assert_eq!(
38 PositiveNonzeroInteger::new(-10),
39 Err(CreationError::Negative),
40 );
41 assert_eq!(PositiveNonzeroInteger::new(0), Err(CreationError::Zero));
42 }
43}