mod inner {
use snafu::{ensure, Snafu};
#[derive(Debug, Snafu)]
pub struct Error(InnerError);
pub fn api() -> Result<i32, Error> {
Ok(a()? + b()?)
}
pub fn not_positive(value: i32) -> Result<i32, Error> {
ensure!(value < 1, TooBig { count: value });
Ok(value)
}
pub fn boxed_inner(value: i32) -> Result<i32, Box<dyn std::error::Error>> {
ensure!(value < 1, TooBig { count: value });
Ok(value)
}
#[derive(Debug, Snafu)]
enum InnerError {
#[snafu(display = r#"("The value {} is too big", count)"#)]
TooBig { count: i32 },
}
fn a() -> Result<i32, InnerError> {
TooBig { count: 1 }.fail()
}
fn b() -> Result<i32, InnerError> {
TooBig { count: 2 }.fail()
}
}
#[test]
fn implements_error() {
fn check<T: std::error::Error>() {}
check::<inner::Error>();
let e = inner::api().unwrap_err();
assert!(e.to_string().contains("too big"));
}
#[test]
fn ensure_opaque() {
assert!(inner::not_positive(-1).is_ok());
let e = inner::not_positive(2).unwrap_err();
assert!(e.to_string().contains("too big"));
}
#[test]
fn ensure_boxed() {
assert!(inner::boxed_inner(-1).is_ok());
let e = inner::boxed_inner(2).unwrap_err();
assert!(e.to_string().contains("too big"));
}