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#![cfg(feature = "std")]
use std::error::Error;
#[macro_use]
extern crate err_derive;
#[derive(Debug, Error)]
#[error(display = "An error has occurred.")]
struct UnitError;
#[test]
fn unit_struct() {
let s = format!("{}", UnitError);
assert_eq!(&s[..], "An error has occurred.");
}
#[derive(Debug, Error)]
#[error(display = "Error code: {}", code)]
struct RecordError {
code: u32,
}
#[test]
fn record_struct() {
let s = format!("{}", RecordError { code: 0 });
assert_eq!(&s[..], "Error code: 0");
}
#[derive(Debug, Error)]
#[error(display = "Error code: {}", _0)]
struct TupleError(i32);
#[test]
fn tuple_struct() {
let s = format!("{}", TupleError(2));
assert_eq!(&s[..], "Error code: 2");
}
#[derive(Debug, Error)]
enum EnumError {
#[error(display = "Error code: {}", code)]
StructVariant { code: i32 },
#[error(display = "Error: {}", _0)]
TupleVariant(&'static str),
#[error(display = "An error has occurred.")]
UnitVariant,
}
#[test]
fn enum_error() {
let s = format!("{}", EnumError::StructVariant { code: 2 });
assert_eq!(&s[..], "Error code: 2");
let s = format!("{}", EnumError::TupleVariant("foobar"));
assert_eq!(&s[..], "Error: foobar");
let s = format!("{}", EnumError::UnitVariant);
assert_eq!(&s[..], "An error has occurred.");
}
#[derive(Debug, Error)]
enum ErrorWithSource {
#[error(display = "tuple error")]
A(#[error(source)] TupleError),
}
#[test]
fn error_with_source() {
let e = ErrorWithSource::A(TupleError(1));
assert!(e.source().is_some());
}
#[derive(Debug, Error)]
enum EnumFrom {
#[error(display = "Tuple error: {}", _0)]
TupleVariant(#[error(source)] UnitError),
#[error(display = "Struct error: {}", inner)]
StructVariant {
#[error(from)]
inner: EnumError,
},
}
#[allow(dead_code)]
#[derive(Debug, Error)]
enum EnumNoFromVariant {
#[error(display = "First error: {}", _0)]
First(#[error(source)] UnitError),
#[error(display = "Second error: {}", _0)]
Second(#[error(source, no_from)] UnitError),
}
#[allow(dead_code)]
#[derive(Debug, Error)]
#[error(no_from)]
enum EnumNoFromStruct {
#[error(display = "First error: {}", _0)]
First(#[error(source)] UnitError),
#[error(display = "Second error: {}", _0)]
Second(#[error(source, from)] UnitError),
}
#[test]
fn from_inner() {
let inner = EnumError::StructVariant { code: 12 };
let outer = EnumFrom::from(inner);
let s = format!("{}", outer);
assert_eq!(&s[..], "Struct error: Error code: 12");
let s = format!("{}", EnumNoFromVariant::from(UnitError));
assert_eq!(&s[..], "First error: An error has occurred.");
let s = format!("{}", EnumNoFromStruct::from(UnitError));
assert_eq!(&s[..], "Second error: An error has occurred.");
}
#[allow(dead_code)]
#[derive(Debug, Error)]
enum EnumAutoBox {
#[error(display = "Boxed error: {}", _0)]
First(#[error(source)] Box<UnitError>),
}
#[test]
fn from_enum_autobox() {
let s = format!("{}", EnumAutoBox::from(UnitError));
assert_eq!(&s[..], "Boxed error: An error has occurred.");
let s = format!("{}", EnumAutoBox::from(Box::new(UnitError)));
assert_eq!(&s[..], "Boxed error: An error has occurred.");
}
#[derive(Debug, Error)]
pub enum TestsNonFieldDisplayValues {
#[error(display = "{}", STATIC_STR)]
A,
#[error(display = "{}", get_static_str())]
B,
#[error(display = "{}", Self::some_method(self))]
C,
#[error(display = "{}", u8::max_value())]
D,
#[error(display = "{}", std::u8::MAX)]
E,
}
impl TestsNonFieldDisplayValues {
fn some_method(&self) -> &'static str {
"some_method"
}
}
static STATIC_STR: &str = "STATIC_STR";
fn get_static_str() -> &'static str {
STATIC_STR
}
#[test]
fn non_field_display() {
let s = format!("{}", TestsNonFieldDisplayValues::A);
assert_eq!(&s, "STATIC_STR");
let s = format!("{}", TestsNonFieldDisplayValues::B);
assert_eq!(&s, "STATIC_STR");
let s = format!("{}", TestsNonFieldDisplayValues::C);
assert_eq!(&s, "some_method");
let s = format!("{}", TestsNonFieldDisplayValues::D);
assert_eq!(&s, "255");
let s = format!("{}", TestsNonFieldDisplayValues::E);
assert_eq!(&s, "255");
}
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