From 889f7cbffa5b7e89fe006c1d35dad42ef6ecc525 Mon Sep 17 00:00:00 2001
From: Josh Triplett <josh@joshtriplett.org>
Date: Sun, 8 Jun 2025 20:11:19 -0700
Subject: [PATCH] Avoid a gratuitous 10s wait in a stress test

`stress_recv_timeout_two_threads`, in the mpmc and mpsc testsuites,
is a stress test of the `recv_timeout` function. This test processes and
ignores timeouts, and just ensures that every sent value gets received.
As such, the exact length of the timeouts is not critical, only that
the timeout and sleep durations ensure that at least one timeout
occurred.

The current tests have 100 iterations, half of which sleep for 200ms,
causing the test to take 10s. This represents around 2/3rds of the
*total* runtime of the `library/std` testsuite.

Reduce this to 50 iterations where half of them sleep for 10ms, causing
the test to take 0.25s.

Add a check that at least one timeout occurred.
---
 library/std/tests/sync/mpmc.rs | 11 ++++++++---
 library/std/tests/sync/mpsc.rs | 11 ++++++++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/library/std/tests/sync/mpmc.rs b/library/std/tests/sync/mpmc.rs
index 78abcb3bcbe1d..594fc2180d83f 100644
--- a/library/std/tests/sync/mpmc.rs
+++ b/library/std/tests/sync/mpmc.rs
@@ -462,8 +462,8 @@ fn oneshot_single_thread_recv_timeout() {
 #[test]
 fn stress_recv_timeout_two_threads() {
     let (tx, rx) = channel();
-    let stress = stress_factor() + 100;
-    let timeout = Duration::from_millis(100);
+    let stress = stress_factor() + 50;
+    let timeout = Duration::from_millis(5);
 
     thread::spawn(move || {
         for i in 0..stress {
@@ -475,18 +475,23 @@ fn stress_recv_timeout_two_threads() {
     });
 
     let mut recv_count = 0;
+    let mut got_timeout = false;
     loop {
         match rx.recv_timeout(timeout) {
             Ok(n) => {
                 assert_eq!(n, 1usize);
                 recv_count += 1;
             }
-            Err(RecvTimeoutError::Timeout) => continue,
+            Err(RecvTimeoutError::Timeout) => {
+                got_timeout = true;
+                continue;
+            }
             Err(RecvTimeoutError::Disconnected) => break,
         }
     }
 
     assert_eq!(recv_count, stress);
+    assert!(got_timeout);
 }
 
 #[test]
diff --git a/library/std/tests/sync/mpsc.rs b/library/std/tests/sync/mpsc.rs
index 1d8edfde44bed..9de4a71987b8e 100644
--- a/library/std/tests/sync/mpsc.rs
+++ b/library/std/tests/sync/mpsc.rs
@@ -425,8 +425,8 @@ fn oneshot_single_thread_recv_timeout() {
 #[test]
 fn stress_recv_timeout_two_threads() {
     let (tx, rx) = channel();
-    let stress = stress_factor() + 100;
-    let timeout = Duration::from_millis(100);
+    let stress = stress_factor() + 50;
+    let timeout = Duration::from_millis(5);
 
     thread::spawn(move || {
         for i in 0..stress {
@@ -438,18 +438,23 @@ fn stress_recv_timeout_two_threads() {
     });
 
     let mut recv_count = 0;
+    let mut got_timeout = false;
     loop {
         match rx.recv_timeout(timeout) {
             Ok(n) => {
                 assert_eq!(n, 1usize);
                 recv_count += 1;
             }
-            Err(RecvTimeoutError::Timeout) => continue,
+            Err(RecvTimeoutError::Timeout) => {
+                got_timeout = true;
+                continue;
+            }
             Err(RecvTimeoutError::Disconnected) => break,
         }
     }
 
     assert_eq!(recv_count, stress);
+    assert!(got_timeout);
 }
 
 #[test]