#![allow(clippy::redundant_clone)]
#![warn(rust_2018_idioms)]
#![cfg(feature = "sync")]
#[cfg(all(target_family = "wasm", not(target_os = "wasi")))]
use wasm_bindgen_test::wasm_bindgen_test as test;
#[cfg(all(target_family = "wasm", not(target_os = "wasi")))]
use wasm_bindgen_test::wasm_bindgen_test as maybe_tokio_test;
#[cfg(not(all(target_family = "wasm", not(target_os = "wasi"))))]
use tokio::test as maybe_tokio_test;
use std::fmt;
use std::sync::Arc;
use tokio::sync::mpsc;
use tokio::sync::mpsc::error::{TryRecvError, TrySendError};
use tokio_test::*;
#[cfg(not(target_family = "wasm"))]
mod support {
pub(crate) mod mpsc_stream;
}
#[allow(unused)]
trait AssertSend: Send {}
impl AssertSend for mpsc::Sender<i32> {}
impl AssertSend for mpsc::Receiver<i32> {}
#[maybe_tokio_test]
async fn send_recv_with_buffer() {
let (tx, mut rx) = mpsc::channel::<i32>(16);
// Using poll_ready / try_send
// let permit assert_ready_ok!(tx.reserve());
let permit = tx.reserve().await.unwrap();
permit.send(1);
// Without poll_ready
tx.try_send(2).unwrap();
drop(tx);
let val = rx.recv().await;
assert_eq!(val, Some(1));
let val = rx.recv().await;
assert_eq!(val, Some(2));
let val = rx.recv().await;
assert!(val.is_none());
}
#[tokio::test]
#[cfg(feature = "full")]
async fn reserve_disarm() {
let (tx, mut rx) = mpsc::channel::<i32>(2);
let tx1 = tx.clone();
let tx2 = tx.clone();
let tx3 = tx.clone();
let tx4 = tx;
// We should be able to `poll_ready` two handles without problem
let permit1 = assert_ok!(tx1.reserve().await);
let permit2 = assert_ok!(tx2.reserve().await);
// But a third should not be ready
let mut r3 = tokio_test::task::spawn(tx3.reserve());
assert_pending!(r3.poll());
let mut r4 = tokio_test::task::spawn(tx4.reserve());
assert_pending!(r4.poll());
// Using one of the reserved slots should allow a new handle to become ready
permit1.send(1);
// We also need to receive for the slot to be free
assert!(!r3.is_woken());
rx.recv().await.unwrap();
// Now there's a free slot!
assert!(r3.is_woken());
assert!(!r4.is_woken());
// Dropping a permit should also open up a slot
drop(permit2);
assert!(r4.is_woken());
let mut r1 = tokio_test::task::spawn(tx1.reserve());
assert_pending!(r1.poll());
}
#[tokio::test]
#[cfg(all(feature = "full", not(target_os = "wasi")))] // Wasi doesn't support threads
async fn send_recv_stream_with_buffer() {
use tokio_stream::StreamExt;
let (tx, rx) = support::mpsc_stream::channel_stream::<i32>(16);
let mut rx = Box::pin(rx);
tokio::spawn(async move {
assert_ok!(tx.send(1).await);
assert_ok!(tx.send(2).await);
});
assert_eq!(Some(1), rx.next().await);
assert_eq!(Some(2), rx.next().await);
assert_eq!(None, rx.next().await);
}
#[tokio::test]
#[cfg(feature = "full")]
async fn async_send_recv_with_buffer() {
let (tx, mut rx) = mpsc::channel(16);
tokio::spawn(async move {
assert_ok!(tx.send(1).await);
assert_ok!(tx.send(2).await);
});
assert_eq!(Some(1), rx.recv().await);
assert_eq!(Some(2), rx.recv().await);
assert_eq!(None, rx.recv().await);
}
#[tokio::test]
#[cfg(feature = "full")]
async fn async_send_recv_many_with_buffer() {
let (tx, mut rx) = mpsc::channel(2);
let mut buffer = Vec::<i32>::with_capacity(3);
// With `limit=0` does not sleep, returns immediately
assert_eq!(0, rx.recv_many(&mut buffer, 0).await);
let handle = tokio::spawn(async move {
assert_ok!(tx.send(1).await);
assert_ok!(tx.send(2).await);
assert_ok!(tx.send(7).await);
assert_ok!(tx.send(0).await);
});
let limit = 3;
let mut recv_count = 0usize;
while recv_count < 4 {
recv_count += rx.recv_many(&mut buffer, limit).await;
assert_eq!(buffer.len(), recv_count);
}
assert_eq!(vec![1, 2, 7, 0], buffer);
assert_eq!(0, rx.recv_many(&mut buffer, limit).await);
handle.await.unwrap();
}
#[tokio::test]
#[cfg(feature = "full")]
async fn start_send_past_cap() {
use std::future::Future;
let mut t1 = tokio_test::task::spawn(());
let (tx1, mut rx) = mpsc::channel(1);
let tx2 = tx1.clone();
assert_ok!(tx1.try_send(()));
let mut r1 = Box::pin(tx1.reserve());
t1.enter(|cx, _| assert_pending!(r1.as_mut().poll(cx)));
{
let mut r2 = tokio_test::task::spawn(tx2.reserve());
assert_pending!(r2.poll());
drop(r1);
assert!(rx.recv().await.is_some());
assert!(r2.is_woken());
assert!(!t1.is_woken());
}
drop(tx1);
drop(tx2);
assert!(rx.recv().await.is_none());
}
#[test]
#[should_panic]
#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
fn buffer_gteq_one() {
mpsc::channel::<i32>(0);
}
#[maybe_tokio_test]
async fn send_recv_unbounded() {
let (tx, mut rx) = mpsc::unbounded_channel::<i32>();
// Using `try_send`
assert_ok!(tx.send(1));
assert_ok!(tx.send(2));
assert_eq!(rx.recv().await, Some(1));
assert_eq!(rx.recv().await, Some(2));
drop(tx);
assert!(rx.recv().await.is_none());
}
#[maybe_tokio_test]
async fn send_recv_many_unbounded() {
let (tx, mut rx) = mpsc::unbounded_channel::<i32>();
let mut buffer: Vec<i32> = Vec::new();
// With `limit=0` does not sleep, returns immediately
rx.recv_many(&mut buffer, 0).await;
assert_eq!(0, buffer.len());
assert_ok!(tx.send(7));
assert_ok!(tx.send(13));
assert_ok!(tx.send(100));
assert_ok!(tx.send(1002));
rx.recv_many(&mut buffer, 0).await;
assert_eq!(0, buffer.len());
let mut count = 0;
while count < 4 {
count += rx.recv_many(&mut buffer, 1).await;
}
assert_eq!(count, 4);
assert_eq!(vec![7, 13, 100, 1002], buffer);
let final_capacity = buffer.capacity();
assert!(final_capacity > 0);
buffer.clear();
assert_ok!(tx.send(5));
assert_ok!(tx.send(6));
assert_ok!(tx.send(7));
assert_ok!(tx.send(2));
// Re-use existing capacity
count = rx.recv_many(&mut buffer, 32).await;
assert_eq!(final_capacity, buffer.capacity());
assert_eq!(count, 4);
assert_eq!(vec![5, 6, 7, 2], buffer);
drop(tx);
// recv_many will immediately return zero if the channel
// is closed and no more messages are waiting
assert_eq!(0, rx.recv_many(&mut buffer, 4).await);
assert!(rx.recv().await.is_none());
}
#[tokio::test]
#[cfg(feature = "full")]
async fn send_recv_many_bounded_capacity() {
let mut buffer: Vec<String> = Vec::with_capacity(9);
let limit = buffer.capacity();
let (tx, mut rx) = mpsc::channel(100);
let mut expected: Vec<String> = (0..limit)
.map(|x: usize| format!("{x}"))
.collect::<Vec<_>>();
for x in expected.clone() {
tx.send(x).await.unwrap()
}
tx.send("one more".to_string()).await.unwrap();
// Here `recv_many` receives all but the last value;
// the initial capacity is adequate, so the buffer does
// not increase in side.
assert_eq!(buffer.capacity(), rx.recv_many(&mut buffer, limit).await);
assert_eq!(expected, buffer);
assert_eq!(limit, buffer.capacity());
// Receive up more values:
assert_eq!(1, rx.recv_many(&mut buffer, limit).await);
assert!(buffer.capacity() > limit);
expected.push("one more".to_string());
assert_eq!(expected, buffer);
tokio::spawn(async move {
tx.send("final".to_string()).await.unwrap();
});
// 'tx' is dropped, but `recv_many` is guaranteed not
// to return 0 as the channel has outstanding permits
assert_eq!(1, rx.recv_many(&mut buffer, limit).await);
expected.push("final".to_string());
assert_eq!(expected, buffer);
// The channel is now closed and `recv_many` returns 0.
assert_eq!(0, rx.recv_many(&mut buffer, limit).await);
assert_eq!(expected, buffer);
}
#[tokio::test]
#[cfg(feature = "full")]
async fn send_recv_many_unbounded_capacity() {
let mut buffer: Vec<String> = Vec::with_capacity(9); // capacity >= 9
let limit = buffer.capacity();
let (tx, mut rx) = mpsc::unbounded_channel();
let mut expected: Vec<String> = (0..limit)
.map(|x: usize| format!("{x}"))
.collect::<Vec<_>>();
for x in expected.clone() {
tx.send(x).unwrap()
}
tx.send("one more".to_string()).unwrap();
// Here `recv_many` receives all but the last value;
// the initial capacity is adequate, so the buffer does
// not increase in side.
assert_eq!(buffer.capacity(), rx.recv_many(&mut buffer, limit).await);
assert_eq!(expected, buffer);
assert_eq!(limit, buffer.capacity());
// Receive up more values:
assert_eq!(1, rx.recv_many(&mut buffer, limit).await);
assert!(buffer.capacity() > limit);
expected.push("one more".to_string());
assert_eq!(expected, buffer);
tokio::spawn(async move {
tx.send("final".to_string()).unwrap();
});
// 'tx' is dropped, but `recv_many` is guaranteed not
// to return 0 as the channel has outstanding permits
assert_eq!(1, rx.recv_many(&mut buffer, limit).await);
expected.push("final".to_string());
assert_eq!(expected, buffer);
// The channel is now closed and `recv_many` returns 0.
assert_eq!(0, rx.recv_many(&mut buffer, limit).await);
assert_eq!(expected, buffer);
}
#[tokio::test]
#[cfg(feature = "full")]
async fn async_send_recv_unbounded() {
let (tx, mut rx) = mpsc::unbounded_channel();
tokio::spawn(async move {
assert_ok!(tx.send(1));
assert_ok!(tx.send(2));
});
assert_eq!(Some(1), rx.recv().await);
assert_eq!(Some(2), rx.recv().await);
assert_eq!(None, rx.recv().await);
}
#[tokio::test]
#[cfg(all(feature = "full", not(target_os = "wasi")))] // Wasi doesn't support threads
async fn send_recv_stream_unbounded() {
use tokio_stream::StreamExt;
let (tx, rx) = support::mpsc_stream::unbounded_channel_stream::<i32>();
let mut rx = Box::pin(rx);
tokio::spawn(async move {
assert_ok!(tx.send(1));
assert_ok!(tx.send(2));
});
assert_eq!(Some(1), rx.next().await);
assert_eq!(Some(2), rx.next().await);
assert_eq!(None, rx.next().await);
}
#[maybe_tokio_test]
async fn no_t_bounds_buffer() {
struct NoImpls;
let (tx, mut rx) = mpsc::channel(100);
// sender should be Debug even though T isn't Debug
is_debug(&tx);
// same with Receiver
is_debug(&rx);
// and sender should be Clone even though T isn't Clone
assert!(tx.clone().try_send(NoImpls).is_ok());
assert!(rx.recv().await.is_some());
}
#[maybe_tokio_test]
async fn no_t_bounds_unbounded() {
struct NoImpls;
let (tx, mut rx) = mpsc::unbounded_channel();
// sender should be Debug even though T isn't Debug
is_debug(&tx);
// same with Receiver
is_debug(&rx);
// and sender should be Clone even though T isn't Clone
assert!(tx.clone().send(NoImpls).is_ok());
assert!(rx.recv().await.is_some());
}
#[tokio::test]
#[cfg(feature = "full")]
async fn send_recv_buffer_limited() {
let (tx, mut rx) = mpsc::channel::<i32>(1);
// Reserve capacity
let p1 = assert_ok!(tx.reserve().await);
// Send first message
p1.send(1);
// Not ready
let mut p2 = tokio_test::task::spawn(tx.reserve());
assert_pending!(p2.poll());
// Take the value
assert!(rx.recv().await.is_some());
// Notified
assert!(p2.is_woken());
// Trying to send fails
assert_err!(tx.try_send(1337));
// Send second
let permit = assert_ready_ok!(p2.poll());
permit.send(2);
assert!(rx.recv().await.is_some());
}
#[maybe_tokio_test]
async fn recv_close_gets_none_idle() {
let (tx, mut rx) = mpsc::channel::<i32>(10);
rx.close();
assert!(rx.recv().await.is_none());
assert_err!(tx.send(1).await);
}
#[tokio::test]
#[cfg(feature = "full")]
async fn recv_close_gets_none_reserved() {
let (tx1, mut rx) = mpsc::channel::<i32>(1);
let tx2 = tx1.clone();
let permit1 = assert_ok!(tx1.reserve().await);
let mut permit2 = tokio_test::task::spawn(tx2.reserve());
assert_pending!(permit2.poll());
rx.close();
assert!(permit2.is_woken());
assert_ready_err!(permit2.poll());
{
let mut recv = tokio_test::task::spawn(rx.recv());
assert_pending!(recv.poll());
permit1.send(123);
assert!(recv.is_woken());
let v = assert_ready!(recv.poll());
assert_eq!(v, Some(123));
}
assert!(rx.recv().await.is_none());
}
#[maybe_tokio_test]
async fn tx_close_gets_none() {
let (_, mut rx) = mpsc::channel::<i32>(10);
assert!(rx.recv().await.is_none());
}
#[maybe_tokio_test]
async fn try_send_fail() {
let (tx, mut rx) = mpsc::channel(1);
tx.try_send("hello").unwrap();
// This should fail
match assert_err!(tx.try_send("fail")) {
TrySendError::Full(..) => {}
_ => panic!(),
}
assert_eq!(rx.recv().await, Some("hello"));
assert_ok!(tx.try_send("goodbye"));
drop(tx);
assert_eq!(rx.recv().await, Some("goodbye"));
assert!(rx.recv().await.is_none());
}
#[maybe_tokio_test]
async fn try_send_fail_with_try_recv() {
let (tx, mut rx) = mpsc::channel(1);
tx.try_send("hello").unwrap();
// This should fail
match assert_err!(tx.try_send("fail")) {
TrySendError::Full(..) => {}
_ => panic!(),
}
assert_eq!(rx.try_recv(), Ok("hello"));
assert_ok!(tx.try_send("goodbye"));
drop(tx);
assert_eq!(rx.try_recv(), Ok("goodbye"));
assert_eq!(rx.try_recv(), Err(TryRecvError::Disconnected));
}
#[maybe_tokio_test]
async fn reserve_many_above_cap() {
const MAX_PERMITS: usize = tokio::sync::Semaphore::MAX_PERMITS;
let (tx, _rx) = mpsc::channel::<()>(1);
assert_err!(tx.reserve_many(2).await);
assert_err!(tx.reserve_many(MAX_PERMITS + 1).await);
assert_err!(tx.reserve_many(usize::MAX).await);
}
#[test]
fn try_reserve_many_zero() {
let (tx, rx) = mpsc::channel::<()>(1);
// Succeeds when not closed.
assert!(assert_ok!(tx.try_reserve_many(0)).next().is_none());
// Even when channel is full.
tx.try_send(()).unwrap();
assert!(assert_ok!(tx.try_reserve_many(0)).next().is_none());
drop(rx);
// Closed error when closed.
assert_eq!(
assert_err!(tx.try_reserve_many(0)),
TrySendError::Closed(())
);
}
#[maybe_tokio_test]
async fn reserve_many_zero() {
let (tx, rx) = mpsc::channel::<()>(1);
// Succeeds when not closed.
assert!(assert_ok!(tx.reserve_many(0).await).next().is_none());
// Even when channel is full.
tx.send(()).await.unwrap();
assert!(assert_ok!(tx.reserve_many(0).await).next().is_none());
drop(rx);
// Closed error when closed.
assert_err!(tx.reserve_many(0).await);
}
#[maybe_tokio_test]
async fn try_reserve_many_edge_cases() {
const MAX_PERMITS: usize = tokio::sync::Semaphore::MAX_PERMITS;
let (tx, rx) = mpsc::channel::<()>(1);
let mut permit = assert_ok!(tx.try_reserve_many(0));
assert!(permit.next().is_none());
let permit = tx.try_reserve_many(MAX_PERMITS + 1);
match assert_err!(permit) {
TrySendError::Full(..) => {}
_ => panic!(),
}
let permit = tx.try_reserve_many(usize::MAX);
match assert_err!(permit) {
TrySendError::Full(..) => {}
_ => panic!(),
}
// Dropping the receiver should close the channel
drop(rx);
assert_err!(tx.reserve_many(0).await);
}
#[maybe_tokio_test]
async fn try_reserve_fails() {
let (tx, mut rx) = mpsc::channel(1);
let permit = tx.try_reserve().unwrap();
// This should fail
match assert_err!(tx.try_reserve()) {
TrySendError::Full(()) => {}
_ => panic!(),
}
permit.send("foo");
assert_eq!(rx.recv().await, Some("foo"));
// Dropping permit releases the slot.
let permit = tx.try_reserve().unwrap();
drop(permit);
let _permit = tx.try_reserve().unwrap();
}
#[maybe_tokio_test]
async fn reserve_many_and_send() {
let (tx, mut rx) = mpsc::channel(100);
for i in 0..100 {
for permit in assert_ok!(tx.reserve_many(i).await) {
permit.send("foo");
assert_eq!(rx.recv().await, Some("foo"));
}
assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));
}
}
#[maybe_tokio_test]
async fn try_reserve_many_and_send() {
let (tx, mut rx) = mpsc::channel(100);
for i in 0..100 {
for permit in assert_ok!(tx.try_reserve_many(i)) {
permit.send("foo");
assert_eq!(rx.recv().await, Some("foo"));
}
assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));
}
}
#[maybe_tokio_test]
async fn reserve_many_on_closed_channel() {
let (tx, rx) = mpsc::channel::<()>(100);
drop(rx);
assert_err!(tx.reserve_many(10).await);
}
#[maybe_tokio_test]
async fn try_reserve_many_on_closed_channel() {
let (tx, rx) = mpsc::channel::<usize>(100);
drop(rx);
match assert_err!(tx.try_reserve_many(10)) {
TrySendError::Closed(()) => {}
_ => panic!(),
};
}
#[maybe_tokio_test]
async fn try_reserve_many_full() {
// Reserve n capacity and send k messages
for n in 1..100 {
for k in 0..n {
let (tx, mut rx) = mpsc::channel::<usize>(n);
let permits = assert_ok!(tx.try_reserve_many(n));
assert_eq!(permits.len(), n);
assert_eq!(tx.capacity(), 0);
match assert_err!(tx.try_reserve_many(1)) {
TrySendError::Full(..) => {}
_ => panic!(),
};
for permit in permits.take(k) {
permit.send(0);
}
// We only used k permits on the n reserved
assert_eq!(tx.capacity(), n - k);
// We can reserve more permits
assert_ok!(tx.try_reserve_many(1));
// But not more than the current capacity
match assert_err!(tx.try_reserve_many(n - k + 1)) {
TrySendError::Full(..) => {}
_ => panic!(),
};
for _i in 0..k {
assert_eq!(rx.recv().await, Some(0));
}
// Now that we've received everything, capacity should be back to n
assert_eq!(tx.capacity(), n);
}
}
}
#[tokio::test]
#[cfg(feature = "full")]
async fn drop_permit_releases_permit() {
// poll_ready reserves capacity, ensure that the capacity is released if tx
// is dropped w/o sending a value.
let (tx1, _rx) = mpsc::channel::<i32>(1);
let tx2 = tx1.clone();
let permit = assert_ok!(tx1.reserve().await);
let mut reserve2 = tokio_test::task::spawn(tx2.reserve());
assert_pending!(reserve2.poll());
drop(permit);
assert!(reserve2.is_woken());
assert_ready_ok!(reserve2.poll());
}
#[maybe_tokio_test]
async fn drop_permit_iterator_releases_permits() {
// poll_ready reserves capacity, ensure that the capacity is released if tx
// is dropped w/o sending a value.
for n in 1..100 {
let (tx1, _rx) = mpsc::channel::<i32>(n);
let tx2 = tx1.clone();
let permits = assert_ok!(tx1.reserve_many(n).await);
let mut reserve2 = tokio_test::task::spawn(tx2.reserve_many(n));
assert_pending!(reserve2.poll());
drop(permits);
assert!(reserve2.is_woken());
let permits = assert_ready_ok!(reserve2.poll());
drop(permits);
assert_eq!(tx1.capacity(), n);
}
}
#[maybe_tokio_test]
async fn dropping_rx_closes_channel() {
let (tx, rx) = mpsc::channel(100);
let msg = Arc::new(());
assert_ok!(tx.try_send(msg.clone()));
drop(rx);
assert_err!(tx.reserve().await);
assert_err!(tx.reserve_many(10).await);
assert_eq!(1, Arc::strong_count(&msg));
}
#[test]
fn dropping_rx_closes_channel_for_try() {
let (tx, rx) = mpsc::channel(100);
let msg = Arc::new(());
tx.try_send(msg.clone()).unwrap();
drop(rx);
assert!(matches!(
tx.try_send(msg.clone()),
Err(TrySendError::Closed(_))
));
assert!(matches!(tx.try_reserve(), Err(TrySendError::Closed(_))));
assert!(matches!(
tx.try_reserve_owned(),
Err(TrySendError::Closed(_))
));
assert_eq!(1, Arc::strong_count(&msg));
}
#[test]
fn unconsumed_messages_are_dropped() {
let msg = Arc::new(());
let (tx, rx) = mpsc::channel(100);
tx.try_send(msg.clone()).unwrap();
assert_eq!(2, Arc::strong_count(&msg));
drop((tx, rx));
assert_eq!(1, Arc::strong_count(&msg));
}
#[test]
#[cfg(all(feature = "full", not(target_os = "wasi")))] // Wasi doesn't support threads
fn blocking_recv() {
let (tx, mut rx) = mpsc::channel::<u8>(1);
let sync_code = std::thread::spawn(move || {
assert_eq!(Some(10), rx.blocking_recv());
});
tokio::runtime::Runtime::new()
.unwrap()
.block_on(async move {
let _ = tx.send(10).await;
});
sync_code.join().unwrap()
}
#[tokio::test]
#[should_panic]
#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
async fn blocking_recv_async() {
let (_tx, mut rx) = mpsc::channel::<()>(1);
let _ = rx.blocking_recv();
}
#[test]
#[cfg(all(feature = "full", not(target_os = "wasi")))] // Wasi doesn't support threads
fn blocking_send() {
let (tx, mut rx) = mpsc::channel::<u8>(1);
let sync_code = std::thread::spawn(move || {
tx.blocking_send(10).unwrap();
});
tokio::runtime::Runtime::new()
.unwrap()
.block_on(async move {
assert_eq!(Some(10), rx.recv().await);
});
sync_code.join().unwrap()
}
#[tokio::test]
#[should_panic]
#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
async fn blocking_send_async() {
let (tx, _rx) = mpsc::channel::<()>(1);
let _ = tx.blocking_send(());
}
#[tokio::test]
#[cfg(feature = "full")]
async fn ready_close_cancel_bounded() {
let (tx, mut rx) = mpsc::channel::<()>(100);
let _tx2 = tx.clone();
let permit = assert_ok!(tx.reserve().await);
rx.close();
let mut recv = tokio_test::task::spawn(rx.recv());
assert_pending!(recv.poll());
drop(permit);
assert!(recv.is_woken());
let val = assert_ready!(recv.poll());
assert!(val.is_none());
}
#[tokio::test]
#[cfg(feature = "full")]
async fn permit_available_not_acquired_close() {
let (tx1, mut rx) = mpsc::channel::<()>(1);
let tx2 = tx1.clone();
let permit1 = assert_ok!(tx1.reserve().await);
let mut permit2 = tokio_test::task::spawn(tx2.reserve());
assert_pending!(permit2.poll());
rx.close();
drop(permit1);
assert!(permit2.is_woken());
drop(permit2);
assert!(rx.recv().await.is_none());
}
#[test]
fn try_recv_bounded() {
let (tx, mut rx) = mpsc::channel(5);
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
assert!(tx.try_send("hello").is_err());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Err(TryRecvError::Empty), rx.try_recv());
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
assert_eq!(Ok("hello"), rx.try_recv());
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
assert!(tx.try_send("hello").is_err());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Err(TryRecvError::Empty), rx.try_recv());
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
tx.try_send("hello").unwrap();
drop(tx);
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Ok("hello"), rx.try_recv());
assert_eq!(Err(TryRecvError::Disconnected), rx.try_recv());
}
#[test]
fn try_recv_unbounded() {
for num in 0..100 {
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..num {
tx.send(i).unwrap();
}
for i in 0..num {
assert_eq!(rx.try_recv(), Ok(i));
}
assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));
drop(tx);
assert_eq!(rx.try_recv(), Err(TryRecvError::Disconnected));
}
}
#[test]
fn try_recv_close_while_empty_bounded() {
let (tx, mut rx) = mpsc::channel::<()>(5);
assert_eq!(Err(TryRecvError::Empty), rx.try_recv());
drop(tx);
assert_eq!(Err(TryRecvError::Disconnected), rx.try_recv());
}
#[test]
fn try_recv_close_while_empty_unbounded() {
let (tx, mut rx) = mpsc::unbounded_channel::<()>();
assert_eq!(Err(TryRecvError::Empty), rx.try_recv());
drop(tx);
assert_eq!(Err(TryRecvError::Disconnected), rx.try_recv());
}
#[tokio::test(start_paused = true)]
#[cfg(feature = "full")]
async fn recv_timeout() {
use tokio::sync::mpsc::error::SendTimeoutError::{Closed, Timeout};
use tokio::time::Duration;
let (tx, rx) = mpsc::channel(5);
assert_eq!(tx.send_timeout(10, Duration::from_secs(1)).await, Ok(()));
assert_eq!(tx.send_timeout(20, Duration::from_secs(1)).await, Ok(()));
assert_eq!(tx.send_timeout(30, Duration::from_secs(1)).await, Ok(()));
assert_eq!(tx.send_timeout(40, Duration::from_secs(1)).await, Ok(()));
assert_eq!(tx.send_timeout(50, Duration::from_secs(1)).await, Ok(()));
assert_eq!(
tx.send_timeout(60, Duration::from_secs(1)).await,
Err(Timeout(60))
);
drop(rx);
assert_eq!(
tx.send_timeout(70, Duration::from_secs(1)).await,
Err(Closed(70))
);
}
#[test]
#[should_panic = "there is no reactor running, must be called from the context of a Tokio 1.x run
time"]
#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
fn recv_timeout_panic() {
use futures::future::FutureExt;
use tokio::time::Duration;
let (tx, _rx) = mpsc::channel(5);
tx.send_timeout(10, Duration::from_secs(1)).now_or_never();
}
// Tests that channel `capacity` changes and `max_capacity` stays the same
#[tokio::test]
async fn test_tx_capacity() {
let (tx, _rx) = mpsc::channel::<()>(10);
// both capacities are same before
assert_eq!(tx.capacity(), 10);
assert_eq!(tx.max_capacity(), 10);
let _permit = tx.reserve().await.unwrap();
// after reserve, only capacity should drop by one
assert_eq!(tx.capacity(), 9);
assert_eq!(tx.max_capacity(), 10);
tx.send(()).await.unwrap();
// after send, capacity should drop by one again
assert_eq!(tx.capacity(), 8);
assert_eq!(tx.max_capacity(), 10);
}
#[tokio::test]
async fn test_rx_is_closed_when_calling_close_with_sender() {
// is_closed should return true after calling close but still has a sender
let (_tx, mut rx) = mpsc::channel::<()>(10);
rx.close();
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_closed_when_dropping_all_senders() {
// is_closed should return true after dropping all senders
let (tx, rx) = mpsc::channel::<()>(10);
let another_tx = tx.clone();
let task = tokio::spawn(async move {
drop(another_tx);
});
drop(tx);
let _ = task.await;
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_not_closed_when_there_are_senders() {
// is_closed should return false when there is a sender
let (_tx, rx) = mpsc::channel::<()>(10);
assert!(!rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_not_closed_when_there_are_senders_and_buffer_filled() {
// is_closed should return false when there is a sender, even if enough messages have been sent to fill the channel
let (tx, rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
assert!(!rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_closed_when_there_are_no_senders_and_there_are_messages() {
// is_closed should return true when there are messages in the buffer, but no senders
let (tx, rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
drop(tx);
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_closed_when_there_are_messages_and_close_is_called() {
// is_closed should return true when there are messages in the buffer, and close is called
let (tx, mut rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
rx.close();
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_not_closed_when_there_are_permits_but_not_senders() {
// is_closed should return false when there is a permit (but no senders)
let (tx, rx) = mpsc::channel::<()>(10);
let _permit = tx.reserve_owned().await.expect("Failed to reserve permit");
assert!(!rx.is_closed());
}
#[tokio::test]
async fn test_rx_is_empty_when_no_messages_were_sent() {
let (_tx, rx) = mpsc::channel::<()>(10);
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_is_not_empty_when_there_are_messages_in_the_buffer() {
let (tx, rx) = mpsc::channel::<()>(10);
assert!(tx.send(()).await.is_ok());
assert!(!rx.is_empty())
}
#[tokio::test]
async fn test_rx_is_not_empty_when_the_buffer_is_full() {
let (tx, rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
assert!(!rx.is_empty())
}
#[tokio::test]
async fn test_rx_is_not_empty_when_all_but_one_messages_are_consumed() {
let (tx, mut rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
for _ in 0..9 {
assert!(rx.recv().await.is_some());
}
assert!(!rx.is_empty())
}
#[tokio::test]
async fn test_rx_is_empty_when_all_messages_are_consumed() {
let (tx, mut rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
while rx.try_recv().is_ok() {}
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_is_empty_all_senders_are_dropped_and_messages_consumed() {
let (tx, mut rx) = mpsc::channel(10);
for i in 0..10 {
assert!(tx.send(i).await.is_ok());
}
drop(tx);
for _ in 0..10 {
assert!(rx.recv().await.is_some());
}
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_len_on_empty_channel() {
let (_tx, rx) = mpsc::channel::<()>(100);
assert_eq!(rx.len(), 0);
}
#[tokio::test]
async fn test_rx_len_on_empty_channel_without_senders() {
// when all senders are dropped, a "closed" value is added to the end of the linked list.
// here we test that the "closed" value does not change the len of the channel.
let (tx, rx) = mpsc::channel::<()>(100);
drop(tx);
assert_eq!(rx.len(), 0);
}
#[tokio::test]
async fn test_rx_len_on_filled_channel() {
let (tx, rx) = mpsc::channel(100);
for i in 0..100 {
assert!(tx.send(i).await.is_ok());
}
assert_eq!(rx.len(), 100);
}
#[tokio::test]
async fn test_rx_len_on_filled_channel_without_senders() {
let (tx, rx) = mpsc::channel(100);
for i in 0..100 {
assert!(tx.send(i).await.is_ok());
}
drop(tx);
assert_eq!(rx.len(), 100);
}
#[tokio::test]
async fn test_rx_len_when_consuming_all_messages() {
let (tx, mut rx) = mpsc::channel(100);
for i in 0..100 {
assert!(tx.send(i).await.is_ok());
assert_eq!(rx.len(), i + 1);
}
drop(tx);
for i in (0..100).rev() {
assert!(rx.recv().await.is_some());
assert_eq!(rx.len(), i);
}
}
#[tokio::test]
async fn test_rx_len_when_close_is_called() {
let (tx, mut rx) = mpsc::channel(100);
tx.send(()).await.unwrap();
rx.close();
assert_eq!(rx.len(), 1);
}
#[tokio::test]
async fn test_rx_len_when_close_is_called_before_dropping_sender() {
let (tx, mut rx) = mpsc::channel(100);
tx.send(()).await.unwrap();
rx.close();
drop(tx);
assert_eq!(rx.len(), 1);
}
#[tokio::test]
async fn test_rx_len_when_close_is_called_after_dropping_sender() {
let (tx, mut rx) = mpsc::channel(100);
tx.send(()).await.unwrap();
drop(tx);
rx.close();
assert_eq!(rx.len(), 1);
}
#[tokio::test]
async fn test_rx_unbounded_is_closed_when_calling_close_with_sender() {
// is_closed should return true after calling close but still has a sender
let (_tx, mut rx) = mpsc::unbounded_channel::<()>();
rx.close();
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_unbounded_is_closed_when_dropping_all_senders() {
// is_closed should return true after dropping all senders
let (tx, rx) = mpsc::unbounded_channel::<()>();
let another_tx = tx.clone();
let task = tokio::spawn(async move {
drop(another_tx);
});
drop(tx);
let _ = task.await;
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_unbounded_is_not_closed_when_there_are_senders() {
// is_closed should return false when there is a sender
let (_tx, rx) = mpsc::unbounded_channel::<()>();
assert!(!rx.is_closed());
}
#[tokio::test]
async fn test_rx_unbounded_is_closed_when_there_are_no_senders_and_there_are_messages() {
// is_closed should return true when there are messages in the buffer, but no senders
let (tx, rx) = mpsc::unbounded_channel();
for i in 0..10 {
assert!(tx.send(i).is_ok());
}
drop(tx);
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_unbounded_is_closed_when_there_are_messages_and_close_is_called() {
// is_closed should return true when there are messages in the buffer, and close is called
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..10 {
assert!(tx.send(i).is_ok());
}
rx.close();
assert!(rx.is_closed());
}
#[tokio::test]
async fn test_rx_unbounded_is_empty_when_no_messages_were_sent() {
let (_tx, rx) = mpsc::unbounded_channel::<()>();
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_unbounded_is_not_empty_when_there_are_messages_in_the_buffer() {
let (tx, rx) = mpsc::unbounded_channel();
assert!(tx.send(()).is_ok());
assert!(!rx.is_empty())
}
#[tokio::test]
async fn test_rx_unbounded_is_not_empty_when_all_but_one_messages_are_consumed() {
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..10 {
assert!(tx.send(i).is_ok());
}
for _ in 0..9 {
assert!(rx.recv().await.is_some());
}
assert!(!rx.is_empty())
}
#[tokio::test]
async fn test_rx_unbounded_is_empty_when_all_messages_are_consumed() {
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..10 {
assert!(tx.send(i).is_ok());
}
while rx.try_recv().is_ok() {}
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_unbounded_is_empty_all_senders_are_dropped_and_messages_consumed() {
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..10 {
assert!(tx.send(i).is_ok());
}
drop(tx);
for _ in 0..10 {
assert!(rx.recv().await.is_some());
}
assert!(rx.is_empty())
}
#[tokio::test]
async fn test_rx_unbounded_len_on_empty_channel() {
let (_tx, rx) = mpsc::unbounded_channel::<()>();
assert_eq!(rx.len(), 0);
}
#[tokio::test]
async fn test_rx_unbounded_len_on_empty_channel_without_senders() {
// when all senders are dropped, a "closed" value is added to the end of the linked list.
// here we test that the "closed" value does not change the len of the channel.
let (tx, rx) = mpsc::unbounded_channel::<()>();
drop(tx);
assert_eq!(rx.len(), 0);
}
#[tokio::test]
async fn test_rx_unbounded_len_with_multiple_messages() {
let (tx, rx) = mpsc::unbounded_channel();
for i in 0..100 {
assert!(tx.send(i).is_ok());
}
assert_eq!(rx.len(), 100);
}
#[tokio::test]
async fn test_rx_unbounded_len_with_multiple_messages_and_dropped_senders() {
let (tx, rx) = mpsc::unbounded_channel();
for i in 0..100 {
assert!(tx.send(i).is_ok());
}
drop(tx);
assert_eq!(rx.len(), 100);
}
#[tokio::test]
async fn test_rx_unbounded_len_when_consuming_all_messages() {
let (tx, mut rx) = mpsc::unbounded_channel();
for i in 0..100 {
assert!(tx.send(i).is_ok());
assert_eq!(rx.len(), i + 1);
}
drop(tx);
for i in (0..100).rev() {
assert!(rx.recv().await.is_some());
assert_eq!(rx.len(), i);
}
}
#[tokio::test]
async fn test_rx_unbounded_len_when_close_is_called() {
let (tx, mut rx) = mpsc::unbounded_channel();
tx.send(()).unwrap();
rx.close();
assert_eq!(rx.len(), 1);
}
#[tokio::test]
async fn test_rx_unbounded_len_when_close_is_called_before_dropping_sender() {
let (tx, mut rx) = mpsc::unbounded_channel();
tx.send(()).unwrap();
rx.close();
drop(tx);
assert_eq!(rx.len(), 1);
}
#[tokio::test]
async fn test_rx_unbounded_len_when_close_is_called_after_dropping_sender() {
let (tx, mut rx) = mpsc::unbounded_channel();
tx.send(()).unwrap();
drop(tx);
rx.close();
assert_eq!(rx.len(), 1);
}
// Regression test for https://github.com/tokio-rs/tokio/issues/6602
#[tokio::test]
async fn test_is_empty_32_msgs() {
let (sender, mut receiver) = mpsc::channel(33);
for value in 1..257 {
sender.send(value).await.unwrap();
receiver.recv().await.unwrap();
assert!(receiver.is_empty(), "{value}. len: {}", receiver.len());
}
}
fn is_debug<T: fmt::Debug>(_: &T) {}
