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|
use async_stream::try_stream;
use futures_core::stream::Stream;
use futures_util::stream::StreamExt;
#[tokio::test]
async fn single_err() {
let s = try_stream! {
if true {
Err("hello")?;
} else {
yield "world";
}
unreachable!();
};
let values: Vec<_> = s.collect().await;
assert_eq!(1, values.len());
assert_eq!(Err("hello"), values[0]);
}
#[tokio::test]
async fn yield_then_err() {
let s = try_stream! {
yield "hello";
Err("world")?;
unreachable!();
};
let values: Vec<_> = s.collect().await;
assert_eq!(2, values.len());
assert_eq!(Ok("hello"), values[0]);
assert_eq!(Err("world"), values[1]);
}
#[tokio::test]
async fn convert_err() {
struct ErrorA(u8);
#[derive(PartialEq, Debug)]
struct ErrorB(u8);
impl From<ErrorA> for ErrorB {
fn from(a: ErrorA) -> ErrorB {
ErrorB(a.0)
}
}
fn test() -> impl Stream<Item = Result<&'static str, ErrorB>> {
try_stream! {
if true {
Err(ErrorA(1))?;
} else {
Err(ErrorB(2))?;
}
yield "unreachable";
}
}
let values: Vec<_> = test().collect().await;
assert_eq!(1, values.len());
assert_eq!(Err(ErrorB(1)), values[0]);
}
#[tokio::test]
async fn multi_try() {
fn test() -> impl Stream<Item = Result<i32, String>> {
try_stream! {
let a = Ok::<_, String>(Ok::<_, String>(123))??;
for _ in (1..10) {
yield a;
}
}
}
let values: Vec<_> = test().collect().await;
assert_eq!(9, values.len());
assert_eq!(
std::iter::repeat(123).take(9).map(Ok).collect::<Vec<_>>(),
values
);
}
|
