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use futures::executor::block_on;
use futures::future::{join_all, ready, Future, JoinAll};
use futures::pin_mut;
use std::fmt::Debug;
#[track_caller]
fn assert_done<T>(actual_fut: impl Future<Output = T>, expected: T)
where
T: PartialEq + Debug,
{
pin_mut!(actual_fut);
let output = block_on(actual_fut);
assert_eq!(output, expected);
}
#[test]
fn collect_collects() {
assert_done(join_all(vec![ready(1), ready(2)]), vec![1, 2]);
assert_done(join_all(vec![ready(1)]), vec![1]);
// REVIEW: should this be implemented?
// assert_done(join_all(Vec::<i32>::new()), vec![]);
// TODO: needs more tests
}
#[test]
fn join_all_iter_lifetime() {
// In futures-rs version 0.1, this function would fail to typecheck due to an overly
// conservative type parameterization of `JoinAll`.
fn sizes(bufs: Vec<&[u8]>) -> impl Future<Output = Vec<usize>> {
let iter = bufs.into_iter().map(|b| ready::<usize>(b.len()));
join_all(iter)
}
assert_done(sizes(vec![&[1, 2, 3], &[], &[0]]), vec![3_usize, 0, 1]);
}
#[test]
fn join_all_from_iter() {
assert_done(vec![ready(1), ready(2)].into_iter().collect::<JoinAll<_>>(), vec![1, 2])
}