Source code
Revision control
Copy as Markdown
Other Tools
use anyhow::anyhow;
use std::error::Error as _;
use std::io;
use thiserror::Error;
#[test]
fn test_transparent_struct() {
#[derive(Error, Debug)]
#[error(transparent)]
struct Error(ErrorKind);
#[derive(Error, Debug)]
enum ErrorKind {
#[error("E0")]
E0,
#[error("E1")]
E1(#[from] io::Error),
}
let error = Error(ErrorKind::E0);
assert_eq!("E0", error.to_string());
assert!(error.source().is_none());
let io = io::Error::new(io::ErrorKind::Other, "oh no!");
let error = Error(ErrorKind::from(io));
assert_eq!("E1", error.to_string());
error.source().unwrap().downcast_ref::<io::Error>().unwrap();
}
#[test]
fn test_transparent_enum() {
#[derive(Error, Debug)]
enum Error {
#[error("this failed")]
This,
#[error(transparent)]
Other(anyhow::Error),
}
let error = Error::This;
assert_eq!("this failed", error.to_string());
let error = Error::Other(anyhow!("inner").context("outer"));
assert_eq!("outer", error.to_string());
assert_eq!("inner", error.source().unwrap().to_string());
}
#[test]
fn test_anyhow() {
#[derive(Error, Debug)]
#[error(transparent)]
struct Any(#[from] anyhow::Error);
let error = Any::from(anyhow!("inner").context("outer"));
assert_eq!("outer", error.to_string());
assert_eq!("inner", error.source().unwrap().to_string());
}
#[test]
fn test_non_static() {
#[derive(Error, Debug)]
#[error(transparent)]
struct Error<'a> {
inner: ErrorKind<'a>,
}
#[derive(Error, Debug)]
enum ErrorKind<'a> {
#[error("unexpected token: {:?}", token)]
Unexpected { token: &'a str },
}
let error = Error {
inner: ErrorKind::Unexpected { token: "error" },
};
assert_eq!("unexpected token: \"error\"", error.to_string());
assert!(error.source().is_none());
}