Improved tests for LockGuard struct.

src/locking.rs

@@ -40,21 +40,55 @@ impl<'a, T> LockGuard<'a, T> {
 #[cfg(test)]
 mod tests {
     use super::LockGuard;
-    use std::sync::RwLock;
-
-    static MY_MUTEX: RwLock<()> = RwLock::new(());
+    use std::{
+        collections::VecDeque,
+        sync::{
+            atomic::{AtomicUsize, Ordering},
+            Arc, Barrier, RwLock,
+        },
+        thread,
+    };
 
     #[test]
-    fn test_shared() {
-        let guard = LockGuard::acquire(&MY_MUTEX, false);
-        assert!(!guard.is_exclusive());
-        assert!(matches!(guard, LockGuard::Shared(_read_guard)));
+    fn test_lock() {
+        static TEST_RWLOCK: RwLock<()> = RwLock::new(());
+        {
+            let guard = LockGuard::acquire(&TEST_RWLOCK, false);
+            assert!(!guard.is_exclusive());
+            assert!(matches!(guard, LockGuard::Shared(_read_guard)));
+        }
+        {
+            let guard = LockGuard::acquire(&TEST_RWLOCK, true);
+            assert!(guard.is_exclusive());
+            assert!(matches!(guard, LockGuard::Exclusive(_write_guard)));
+        }
     }
 
     #[test]
-    fn test_exclusive() {
-        let guard = LockGuard::acquire(&MY_MUTEX, true);
-        assert!(guard.is_exclusive());
-        assert!(matches!(guard, LockGuard::Exclusive(_write_guard)));
+    fn test_threads() {
+        static TEST_RWLOCK: RwLock<()> = RwLock::new(());
+        const THREAD_COUNT: usize = 32usize;
+        let barrier = Arc::new(Barrier::new(THREAD_COUNT));
+        let mut thread_list = VecDeque::with_capacity(THREAD_COUNT);
+        let counter = Arc::new(AtomicUsize::new(0usize));
+        for _tid in 0..THREAD_COUNT {
+            let thread_barrier = Arc::clone(&barrier);
+            let thread_counter = Arc::clone(&counter);
+            thread_list.push_back(thread::spawn(move || {
+                let is_leader = thread_barrier.wait().is_leader();
+                for _iteration in 0..100000 {
+                    let guard = LockGuard::acquire(&TEST_RWLOCK, is_leader);
+                    let value = thread_counter.fetch_add(1usize, Ordering::Relaxed);
+                    if guard.is_exclusive() {
+                        assert_eq!(value, 0usize, "Invalid counter value!");
+                    }
+                    thread::yield_now();
+                    thread_counter.fetch_sub(1usize, Ordering::Relaxed);
+                }
+            }));
+        }
+        for thread in thread_list.drain(..) {
+            thread.join().unwrap();
+        }
     }
 }