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#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
use tokio::runtime::Runtime;
use tokio::sync::{mpsc, oneshot};
use tokio_test::{assert_err, assert_ok};
use std::thread;
use std::time::Duration;
#[test]
fn spawned_task_does_not_progress_without_block_on() {
let (tx, mut rx) = oneshot::channel();
let rt = rt();
rt.spawn(async move {
assert_ok!(tx.send("hello"));
});
thread::sleep(Duration::from_millis(50));
assert_err!(rx.try_recv());
let out = rt.block_on(async { assert_ok!(rx.await) });
assert_eq!(out, "hello");
}
#[test]
fn no_extra_poll() {
use pin_project_lite::pin_project;
use std::pin::Pin;
use std::sync::{
atomic::{AtomicUsize, Ordering::SeqCst},
Arc,
};
use std::task::{Context, Poll};
use tokio::stream::{Stream, StreamExt};
pin_project! {
struct TrackPolls<S> {
npolls: Arc<AtomicUsize>,
#[pin]
s: S,
}
}
impl<S> Stream for TrackPolls<S>
where
S: Stream,
{
type Item = S::Item;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = self.project();
this.npolls.fetch_add(1, SeqCst);
this.s.poll_next(cx)
}
}
let (tx, rx) = mpsc::unbounded_channel();
let mut rx = TrackPolls {
npolls: Arc::new(AtomicUsize::new(0)),
s: rx,
};
let npolls = Arc::clone(&rx.npolls);
let rt = rt();
rt.spawn(async move { while rx.next().await.is_some() {} });
rt.block_on(async {
tokio::task::yield_now().await;
});
// should have been polled exactly once: the initial poll
assert_eq!(npolls.load(SeqCst), 1);
tx.send(()).unwrap();
rt.block_on(async {
tokio::task::yield_now().await;
});
// should have been polled twice more: once to yield Some(), then once to yield Pending
assert_eq!(npolls.load(SeqCst), 1 + 2);
drop(tx);
rt.block_on(async {
tokio::task::yield_now().await;
});
// should have been polled once more: to yield None
assert_eq!(npolls.load(SeqCst), 1 + 2 + 1);
}
#[test]
fn acquire_mutex_in_drop() {
use futures::future::pending;
use tokio::task;
let (tx1, rx1) = oneshot::channel();
let (tx2, rx2) = oneshot::channel();
let rt = rt();
rt.spawn(async move {
let _ = rx2.await;
unreachable!();
});
rt.spawn(async move {
let _ = rx1.await;
tx2.send(()).unwrap();
unreachable!();
});
// Spawn a task that will never notify
rt.spawn(async move {
pending::<()>().await;
tx1.send(()).unwrap();
});
// Tick the loop
rt.block_on(async {
task::yield_now().await;
});
// Drop the rt
drop(rt);
}
fn rt() -> Runtime {
tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.unwrap()
}
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