sync: make add_permits panic with usize::MAX >> 3 permits (#3188)

1 files changed, 14 insertions, 0 deletions

diff --git a/tokio/tests/sync_semaphore.rs b/tokio/tests/sync_semaphore.rs
index 1cb0c749..a33b878b 100644
--- a/tokio/tests/sync_semaphore.rs
+++ b/tokio/tests/sync_semaphore.rs
@@ -79,3 +79,17 @@ async fn stresstest() {
     let _p5 = sem.try_acquire().unwrap();
     assert!(sem.try_acquire().is_err());
 }
+
+#[test]
+fn add_max_amount_permits() {
+    let s = tokio::sync::Semaphore::new(0);
+    s.add_permits(usize::MAX >> 3);
+    assert_eq!(s.available_permits(), usize::MAX >> 3);
+}
+
+#[test]
+#[should_panic]
+fn add_more_than_max_amount_permits() {
+    let s = tokio::sync::Semaphore::new(1);
+    s.add_permits(usize::MAX >> 3);
+}