1 #![allow(clippy::redundant_clone)]
2 #![warn(rust_2018_idioms)]
3 #![cfg(feature = "full")]
4
5 use std::thread;
6 use tokio::runtime::Runtime;
7 use tokio::sync::mpsc;
8 use tokio::sync::mpsc::error::TrySendError;
9 use tokio_test::task;
10 use tokio_test::{
11 assert_err, assert_ok, assert_pending, assert_ready, assert_ready_err, assert_ready_ok,
12 };
13
14 use std::sync::Arc;
15
16 mod support {
17 pub(crate) mod mpsc_stream;
18 }
19
20 trait AssertSend: Send {}
21 impl AssertSend for mpsc::Sender<i32> {}
22 impl AssertSend for mpsc::Receiver<i32> {}
23
24 #[tokio::test]
send_recv_with_buffer()25 async fn send_recv_with_buffer() {
26 let (tx, mut rx) = mpsc::channel::<i32>(16);
27
28 // Using poll_ready / try_send
29 // let permit assert_ready_ok!(tx.reserve());
30 let permit = tx.reserve().await.unwrap();
31 permit.send(1);
32
33 // Without poll_ready
34 tx.try_send(2).unwrap();
35
36 drop(tx);
37
38 let val = rx.recv().await;
39 assert_eq!(val, Some(1));
40
41 let val = rx.recv().await;
42 assert_eq!(val, Some(2));
43
44 let val = rx.recv().await;
45 assert!(val.is_none());
46 }
47
48 #[tokio::test]
reserve_disarm()49 async fn reserve_disarm() {
50 let (tx, mut rx) = mpsc::channel::<i32>(2);
51 let tx1 = tx.clone();
52 let tx2 = tx.clone();
53 let tx3 = tx.clone();
54 let tx4 = tx;
55
56 // We should be able to `poll_ready` two handles without problem
57 let permit1 = assert_ok!(tx1.reserve().await);
58 let permit2 = assert_ok!(tx2.reserve().await);
59
60 // But a third should not be ready
61 let mut r3 = task::spawn(tx3.reserve());
62 assert_pending!(r3.poll());
63
64 let mut r4 = task::spawn(tx4.reserve());
65 assert_pending!(r4.poll());
66
67 // Using one of the reserved slots should allow a new handle to become ready
68 permit1.send(1);
69
70 // We also need to receive for the slot to be free
71 assert!(!r3.is_woken());
72 rx.recv().await.unwrap();
73 // Now there's a free slot!
74 assert!(r3.is_woken());
75 assert!(!r4.is_woken());
76
77 // Dropping a permit should also open up a slot
78 drop(permit2);
79 assert!(r4.is_woken());
80
81 let mut r1 = task::spawn(tx1.reserve());
82 assert_pending!(r1.poll());
83 }
84
85 #[tokio::test]
send_recv_stream_with_buffer()86 async fn send_recv_stream_with_buffer() {
87 use tokio_stream::StreamExt;
88
89 let (tx, rx) = support::mpsc_stream::channel_stream::<i32>(16);
90 let mut rx = Box::pin(rx);
91
92 tokio::spawn(async move {
93 assert_ok!(tx.send(1).await);
94 assert_ok!(tx.send(2).await);
95 });
96
97 assert_eq!(Some(1), rx.next().await);
98 assert_eq!(Some(2), rx.next().await);
99 assert_eq!(None, rx.next().await);
100 }
101
102 #[tokio::test]
async_send_recv_with_buffer()103 async fn async_send_recv_with_buffer() {
104 let (tx, mut rx) = mpsc::channel(16);
105
106 tokio::spawn(async move {
107 assert_ok!(tx.send(1).await);
108 assert_ok!(tx.send(2).await);
109 });
110
111 assert_eq!(Some(1), rx.recv().await);
112 assert_eq!(Some(2), rx.recv().await);
113 assert_eq!(None, rx.recv().await);
114 }
115
116 #[tokio::test]
start_send_past_cap()117 async fn start_send_past_cap() {
118 use std::future::Future;
119
120 let mut t1 = task::spawn(());
121
122 let (tx1, mut rx) = mpsc::channel(1);
123 let tx2 = tx1.clone();
124
125 assert_ok!(tx1.try_send(()));
126
127 let mut r1 = Box::pin(tx1.reserve());
128 t1.enter(|cx, _| assert_pending!(r1.as_mut().poll(cx)));
129
130 {
131 let mut r2 = task::spawn(tx2.reserve());
132 assert_pending!(r2.poll());
133
134 drop(r1);
135
136 assert!(rx.recv().await.is_some());
137
138 assert!(r2.is_woken());
139 assert!(!t1.is_woken());
140 }
141
142 drop(tx1);
143 drop(tx2);
144
145 assert!(rx.recv().await.is_none());
146 }
147
148 #[test]
149 #[should_panic]
buffer_gteq_one()150 fn buffer_gteq_one() {
151 mpsc::channel::<i32>(0);
152 }
153
154 #[tokio::test]
send_recv_unbounded()155 async fn send_recv_unbounded() {
156 let (tx, mut rx) = mpsc::unbounded_channel::<i32>();
157
158 // Using `try_send`
159 assert_ok!(tx.send(1));
160 assert_ok!(tx.send(2));
161
162 assert_eq!(rx.recv().await, Some(1));
163 assert_eq!(rx.recv().await, Some(2));
164
165 drop(tx);
166
167 assert!(rx.recv().await.is_none());
168 }
169
170 #[tokio::test]
async_send_recv_unbounded()171 async fn async_send_recv_unbounded() {
172 let (tx, mut rx) = mpsc::unbounded_channel();
173
174 tokio::spawn(async move {
175 assert_ok!(tx.send(1));
176 assert_ok!(tx.send(2));
177 });
178
179 assert_eq!(Some(1), rx.recv().await);
180 assert_eq!(Some(2), rx.recv().await);
181 assert_eq!(None, rx.recv().await);
182 }
183
184 #[tokio::test]
send_recv_stream_unbounded()185 async fn send_recv_stream_unbounded() {
186 use tokio_stream::StreamExt;
187
188 let (tx, rx) = support::mpsc_stream::unbounded_channel_stream::<i32>();
189
190 let mut rx = Box::pin(rx);
191
192 tokio::spawn(async move {
193 assert_ok!(tx.send(1));
194 assert_ok!(tx.send(2));
195 });
196
197 assert_eq!(Some(1), rx.next().await);
198 assert_eq!(Some(2), rx.next().await);
199 assert_eq!(None, rx.next().await);
200 }
201
202 #[tokio::test]
no_t_bounds_buffer()203 async fn no_t_bounds_buffer() {
204 struct NoImpls;
205
206 let (tx, mut rx) = mpsc::channel(100);
207
208 // sender should be Debug even though T isn't Debug
209 println!("{:?}", tx);
210 // same with Receiver
211 println!("{:?}", rx);
212 // and sender should be Clone even though T isn't Clone
213 assert!(tx.clone().try_send(NoImpls).is_ok());
214
215 assert!(rx.recv().await.is_some());
216 }
217
218 #[tokio::test]
no_t_bounds_unbounded()219 async fn no_t_bounds_unbounded() {
220 struct NoImpls;
221
222 let (tx, mut rx) = mpsc::unbounded_channel();
223
224 // sender should be Debug even though T isn't Debug
225 println!("{:?}", tx);
226 // same with Receiver
227 println!("{:?}", rx);
228 // and sender should be Clone even though T isn't Clone
229 assert!(tx.clone().send(NoImpls).is_ok());
230
231 assert!(rx.recv().await.is_some());
232 }
233
234 #[tokio::test]
send_recv_buffer_limited()235 async fn send_recv_buffer_limited() {
236 let (tx, mut rx) = mpsc::channel::<i32>(1);
237
238 // Reserve capacity
239 let p1 = assert_ok!(tx.reserve().await);
240
241 // Send first message
242 p1.send(1);
243
244 // Not ready
245 let mut p2 = task::spawn(tx.reserve());
246 assert_pending!(p2.poll());
247
248 // Take the value
249 assert!(rx.recv().await.is_some());
250
251 // Notified
252 assert!(p2.is_woken());
253
254 // Trying to send fails
255 assert_err!(tx.try_send(1337));
256
257 // Send second
258 let permit = assert_ready_ok!(p2.poll());
259 permit.send(2);
260
261 assert!(rx.recv().await.is_some());
262 }
263
264 #[tokio::test]
recv_close_gets_none_idle()265 async fn recv_close_gets_none_idle() {
266 let (tx, mut rx) = mpsc::channel::<i32>(10);
267
268 rx.close();
269
270 assert!(rx.recv().await.is_none());
271
272 assert_err!(tx.send(1).await);
273 }
274
275 #[tokio::test]
recv_close_gets_none_reserved()276 async fn recv_close_gets_none_reserved() {
277 let (tx1, mut rx) = mpsc::channel::<i32>(1);
278 let tx2 = tx1.clone();
279
280 let permit1 = assert_ok!(tx1.reserve().await);
281 let mut permit2 = task::spawn(tx2.reserve());
282 assert_pending!(permit2.poll());
283
284 rx.close();
285
286 assert!(permit2.is_woken());
287 assert_ready_err!(permit2.poll());
288
289 {
290 let mut recv = task::spawn(rx.recv());
291 assert_pending!(recv.poll());
292
293 permit1.send(123);
294 assert!(recv.is_woken());
295
296 let v = assert_ready!(recv.poll());
297 assert_eq!(v, Some(123));
298 }
299
300 assert!(rx.recv().await.is_none());
301 }
302
303 #[tokio::test]
tx_close_gets_none()304 async fn tx_close_gets_none() {
305 let (_, mut rx) = mpsc::channel::<i32>(10);
306 assert!(rx.recv().await.is_none());
307 }
308
309 #[tokio::test]
try_send_fail()310 async fn try_send_fail() {
311 let (tx, mut rx) = mpsc::channel(1);
312
313 tx.try_send("hello").unwrap();
314
315 // This should fail
316 match assert_err!(tx.try_send("fail")) {
317 TrySendError::Full(..) => {}
318 _ => panic!(),
319 }
320
321 assert_eq!(rx.recv().await, Some("hello"));
322
323 assert_ok!(tx.try_send("goodbye"));
324 drop(tx);
325
326 assert_eq!(rx.recv().await, Some("goodbye"));
327 assert!(rx.recv().await.is_none());
328 }
329
330 #[tokio::test]
try_reserve_fails()331 async fn try_reserve_fails() {
332 let (tx, mut rx) = mpsc::channel(1);
333
334 let permit = tx.try_reserve().unwrap();
335
336 // This should fail
337 match assert_err!(tx.try_reserve()) {
338 TrySendError::Full(()) => {}
339 _ => panic!(),
340 }
341
342 permit.send("foo");
343
344 assert_eq!(rx.recv().await, Some("foo"));
345
346 // Dropping permit releases the slot.
347 let permit = tx.try_reserve().unwrap();
348 drop(permit);
349
350 let _permit = tx.try_reserve().unwrap();
351 }
352
353 #[tokio::test]
drop_permit_releases_permit()354 async fn drop_permit_releases_permit() {
355 // poll_ready reserves capacity, ensure that the capacity is released if tx
356 // is dropped w/o sending a value.
357 let (tx1, _rx) = mpsc::channel::<i32>(1);
358 let tx2 = tx1.clone();
359
360 let permit = assert_ok!(tx1.reserve().await);
361
362 let mut reserve2 = task::spawn(tx2.reserve());
363 assert_pending!(reserve2.poll());
364
365 drop(permit);
366
367 assert!(reserve2.is_woken());
368 assert_ready_ok!(reserve2.poll());
369 }
370
371 #[tokio::test]
dropping_rx_closes_channel()372 async fn dropping_rx_closes_channel() {
373 let (tx, rx) = mpsc::channel(100);
374
375 let msg = Arc::new(());
376 assert_ok!(tx.try_send(msg.clone()));
377
378 drop(rx);
379 assert_err!(tx.reserve().await);
380 assert_eq!(1, Arc::strong_count(&msg));
381 }
382
383 #[test]
dropping_rx_closes_channel_for_try()384 fn dropping_rx_closes_channel_for_try() {
385 let (tx, rx) = mpsc::channel(100);
386
387 let msg = Arc::new(());
388 tx.try_send(msg.clone()).unwrap();
389
390 drop(rx);
391
392 {
393 let err = assert_err!(tx.try_send(msg.clone()));
394 match err {
395 TrySendError::Closed(..) => {}
396 _ => panic!(),
397 }
398 }
399
400 assert_eq!(1, Arc::strong_count(&msg));
401 }
402
403 #[test]
unconsumed_messages_are_dropped()404 fn unconsumed_messages_are_dropped() {
405 let msg = Arc::new(());
406
407 let (tx, rx) = mpsc::channel(100);
408
409 tx.try_send(msg.clone()).unwrap();
410
411 assert_eq!(2, Arc::strong_count(&msg));
412
413 drop((tx, rx));
414
415 assert_eq!(1, Arc::strong_count(&msg));
416 }
417
418 #[test]
blocking_recv()419 fn blocking_recv() {
420 let (tx, mut rx) = mpsc::channel::<u8>(1);
421
422 let sync_code = thread::spawn(move || {
423 assert_eq!(Some(10), rx.blocking_recv());
424 });
425
426 Runtime::new().unwrap().block_on(async move {
427 let _ = tx.send(10).await;
428 });
429 sync_code.join().unwrap()
430 }
431
432 #[tokio::test]
433 #[should_panic]
blocking_recv_async()434 async fn blocking_recv_async() {
435 let (_tx, mut rx) = mpsc::channel::<()>(1);
436 let _ = rx.blocking_recv();
437 }
438
439 #[test]
blocking_send()440 fn blocking_send() {
441 let (tx, mut rx) = mpsc::channel::<u8>(1);
442
443 let sync_code = thread::spawn(move || {
444 tx.blocking_send(10).unwrap();
445 });
446
447 Runtime::new().unwrap().block_on(async move {
448 assert_eq!(Some(10), rx.recv().await);
449 });
450 sync_code.join().unwrap()
451 }
452
453 #[tokio::test]
454 #[should_panic]
blocking_send_async()455 async fn blocking_send_async() {
456 let (tx, _rx) = mpsc::channel::<()>(1);
457 let _ = tx.blocking_send(());
458 }
459
460 #[tokio::test]
ready_close_cancel_bounded()461 async fn ready_close_cancel_bounded() {
462 let (tx, mut rx) = mpsc::channel::<()>(100);
463 let _tx2 = tx.clone();
464
465 let permit = assert_ok!(tx.reserve().await);
466
467 rx.close();
468
469 let mut recv = task::spawn(rx.recv());
470 assert_pending!(recv.poll());
471
472 drop(permit);
473
474 assert!(recv.is_woken());
475 let val = assert_ready!(recv.poll());
476 assert!(val.is_none());
477 }
478
479 #[tokio::test]
permit_available_not_acquired_close()480 async fn permit_available_not_acquired_close() {
481 let (tx1, mut rx) = mpsc::channel::<()>(1);
482 let tx2 = tx1.clone();
483
484 let permit1 = assert_ok!(tx1.reserve().await);
485
486 let mut permit2 = task::spawn(tx2.reserve());
487 assert_pending!(permit2.poll());
488
489 rx.close();
490
491 drop(permit1);
492 assert!(permit2.is_woken());
493
494 drop(permit2);
495 assert!(rx.recv().await.is_none());
496 }
497