blob: e5f3d39e5a4c1eb0cf4b633e5e0f928c50d3831c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
#[derive(PartialEq, Debug)]
enum CreationError {
Negative,
Zero,
}
#[derive(PartialEq, Debug)]
struct PositiveNonzeroInteger(u64);
impl PositiveNonzeroInteger {
fn new(value: i64) -> Result<Self, CreationError> {
// TODO: This function shouldn't always return an `Ok`.
// Read the tests below to clarify what should be returned.
if value < 0 {
return Err(CreationError::Negative);
}
if value == 0 {
return Err(CreationError::Zero);
}
Ok(Self(value as u64))
}
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_creation() {
assert_eq!(
PositiveNonzeroInteger::new(10),
Ok(PositiveNonzeroInteger(10)),
);
assert_eq!(
PositiveNonzeroInteger::new(-10),
Err(CreationError::Negative),
);
assert_eq!(PositiveNonzeroInteger::new(0), Err(CreationError::Zero));
}
}
|
