rustlings/error_handling/result1.rs
Carol (Nichols || Goulding) d145c6334f Start an error handling section and move the result exercise there
I think this is a better categorization than "standard library types".
2016-04-16 10:53:39 -04:00

43 lines
881 B
Rust

// Make this test pass! Scroll down for hints :)
#[derive(PartialEq,Debug)]
struct PositiveNonzeroInteger(u64);
#[derive(PartialEq,Debug)]
enum CreationError {
Negative,
Zero,
}
impl PositiveNonzeroInteger {
fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
Ok(PositiveNonzeroInteger(value as u64))
}
}
#[test]
fn test_creation() {
assert!(PositiveNonzeroInteger::new(10).is_ok());
assert_eq!(Err(CreationError::Negative), PositiveNonzeroInteger::new(-10));
assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
}
// `PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
// It should be doing some checking, returning an `Err` result if those checks fail, and only
// returning an `Ok` result if those checks determine that everything is... okay :)