cleanup on drop for utils::mutex_map.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/tests.rs

@@ -81,3 +81,56 @@ fn checked_add_overflow() {
 	let res = checked!(a + 1).expect("overflow");
 	assert_eq!(res, 0);
 }
+
+#[tokio::test]
+async fn mutex_map_cleanup() {
+	use crate::utils::MutexMap;
+
+	let map = MutexMap::<String, ()>::new();
+
+	let lock = map.lock("foo").await;
+	assert!(!map.is_empty(), "map must not be empty");
+
+	drop(lock);
+	assert!(map.is_empty(), "map must be empty");
+}
+
+#[tokio::test]
+async fn mutex_map_contend() {
+	use std::sync::Arc;
+
+	use tokio::sync::Barrier;
+
+	use crate::utils::MutexMap;
+
+	let map = Arc::new(MutexMap::<String, ()>::new());
+	let seq = Arc::new([Barrier::new(2), Barrier::new(2)]);
+	let str = "foo".to_owned();
+
+	let seq_ = seq.clone();
+	let map_ = map.clone();
+	let str_ = str.clone();
+	let join_a = tokio::spawn(async move {
+		let _lock = map_.lock(&str_).await;
+		assert!(!map_.is_empty(), "A0 must not be empty");
+		seq_[0].wait().await;
+		assert!(map_.contains(&str_), "A1 must contain key");
+	});
+
+	let seq_ = seq.clone();
+	let map_ = map.clone();
+	let str_ = str.clone();
+	let join_b = tokio::spawn(async move {
+		let _lock = map_.lock(&str_).await;
+		assert!(!map_.is_empty(), "B0 must not be empty");
+		seq_[1].wait().await;
+		assert!(map_.contains(&str_), "B1 must contain key");
+	});
+
+	seq[0].wait().await;
+	assert!(map.contains(&str), "Must contain key");
+	seq[1].wait().await;
+
+	tokio::try_join!(join_b, join_a).expect("joined");
+	assert!(map.is_empty(), "Must be empty");
+}