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firefox/third_party/rust/tokio-util/tests/poll_semaphore.rs
Daniel Baumann 5e9a113729
Adding upstream version 140.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-25 09:37:52 +02:00

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Rust

use std::future::Future;
use std::sync::Arc;
use std::task::Poll;
use tokio::sync::{OwnedSemaphorePermit, Semaphore};
use tokio_util::sync::PollSemaphore;
type SemRet = Option<OwnedSemaphorePermit>;
fn semaphore_poll(
sem: &mut PollSemaphore,
) -> tokio_test::task::Spawn<impl Future<Output = SemRet> + '_> {
let fut = futures::future::poll_fn(move |cx| sem.poll_acquire(cx));
tokio_test::task::spawn(fut)
}
#[tokio::test]
async fn it_works() {
let sem = Arc::new(Semaphore::new(1));
let mut poll_sem = PollSemaphore::new(sem.clone());
let permit = sem.acquire().await.unwrap();
let mut poll = semaphore_poll(&mut poll_sem);
assert!(poll.poll().is_pending());
drop(permit);
assert!(matches!(poll.poll(), Poll::Ready(Some(_))));
drop(poll);
sem.close();
assert!(semaphore_poll(&mut poll_sem).await.is_none());
// Check that it is fused.
assert!(semaphore_poll(&mut poll_sem).await.is_none());
assert!(semaphore_poll(&mut poll_sem).await.is_none());
}