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#![cfg(feature="std")]
use snafu::{prelude::*, Whatever};
type Result<T, E = Whatever> = std::result::Result<T, E>;
// Using fully-qualified paths here to ensure the module's imports are
// minimal
#[derive(Debug, snafu::Snafu)]
pub struct UnderlyingError;
pub fn underlying(success: bool) -> Result<i32, UnderlyingError> {
snafu::ensure!(success, UnderlyingSnafu);
Ok(1)
}
#[test]
fn implements_error() {
fn check<T: std::error::Error>() {}
check::<Whatever>();
}
#[test]
fn does_not_need_a_cause() {
use std::error::Error as _;
fn exercise(success: bool) -> Result<i32> {
if !success {
whatever!("I caused a problem {}", 42);
}
Ok(1)
}
let e = exercise(false).unwrap_err();
assert!(e.source().is_none());
}
#[test]
fn can_wrap_cause_with_a_formatted_string_via_macro() {
use std::error::Error as _;
fn exercise(success: bool) -> Result<i32> {
let v = whatever!(underlying(success), "Something else happened {}", 42);
Ok(v + 1)
}
assert!(matches!(exercise(true), Ok(2)));
let e = exercise(false).unwrap_err();
assert_eq!("Something else happened 42", e.to_string());
let src = e.source().expect("Must have a source");
let src = src.downcast_ref::<UnderlyingError>();
assert!(src.is_some());
}
#[test]
fn can_wrap_cause_with_a_formatted_string_via_trait() {
use std::error::Error as _;
fn exercise(success: bool) -> Result<i32> {
let v = underlying(success)
.with_whatever_context(|_| format!("Something else happened {}", 42))?;
Ok(v + 1)
}
assert!(matches!(exercise(true), Ok(2)));
let e = exercise(false).unwrap_err();
assert_eq!("Something else happened 42", e.to_string());
let src = e.source().expect("Must have a source");
let src = src.downcast_ref::<UnderlyingError>();
assert!(src.is_some());
}
#[test]
fn can_be_recursive() {
use std::error::Error as _;
fn inner(success: bool) -> Result<i32> {
if !success {
whatever!("Inner error");
}
Ok(1)
}
fn outer(success: bool) -> Result<i32> {
let v = whatever!(inner(success), "Outer error");
Ok(v + 1)
}
assert!(matches!(outer(true), Ok(2)));
let outer_error = outer(false).unwrap_err();
let inner_error = outer_error.source().expect("Must have a source");
assert!(inner_error.downcast_ref::<Whatever>().is_some());
assert!(inner_error.source().is_none());
}
#[test]
fn has_a_backtrace() {
use snafu::ErrorCompat;
fn exercise(success: bool) -> Result<i32> {
let v = whatever!(underlying(success), "Something else happened {}", 42);
Ok(v + 1)
}
let e = exercise(false).unwrap_err();
let bt = ErrorCompat::backtrace(&e).expect("Must have a backtrace");
assert_eq!("disabled backtrace", bt.to_string());
}
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