#[macro_use]
extern crate derive_more;
extern crate erroneous;

use erroneous::Error;
use std::error::Error as _;

#[derive(Debug, Display, Error)]
#[display(fmt = "A")]
struct A;

#[derive(Debug, Display, Error)]
#[display(fmt = "B")]
struct B(#[error(source)] A);

#[derive(Debug, Display, Error)]
#[display(fmt = "C")]
struct C(#[error(source)] B);

#[derive(Debug, Display, Error)]
#[display(fmt = "{}", _0)]
struct D(#[error(defer)] C);

#[test]
fn source() {
	let e = D(C(B(A)));
	let e = e.source().unwrap();
	assert!(e.is::<B>());
	let e = e.source().unwrap();
	assert!(e.is::<A>());
	assert!(e.source().is_none());
}

#[test]
fn iter() {
	let mut e = D(C(B(A))).iter();
	assert!(e.next().unwrap().is::<D>());
	assert!(e.next().unwrap().is::<B>());
	assert!(e.next().unwrap().is::<A>());
	assert!(e.next().is_none());
}