std/sync: add test for Once

std/runtime/lock.jule

@@ -65,7 +65,7 @@ const mutexWaiterShift = 3
 const starvationThresholdNs = 1_100_000
 
 // Advanced mutex implementation for common and public use.
-// See the sync::Mutex for documentation.
+// See the [sync::Mutex] for documentation.
 // This implementation derived from the original Go code,
 // but it may work different paritially.
 // For the original Go code, see the sync.Mutex of the Go stdlib.
@@ -76,7 +76,7 @@ struct mutex {
 
 impl mutex {
 	// Locks the mutex.
-	// See the [sync::Mutex.Lock] for documentation.
+	// See the [sync::Mutex] for documentation.
 	fn lock(self) {
 		// Fast path: grab unlocked mutex.
 		if atomicCompareAndSwap(self.state, 0, mutexLocked, atomicSeqCst) {
@@ -170,7 +170,7 @@ impl mutex {
 	}
 
 	// Tries to lock the mutex.
-	// See the [sync::Mutex.TryLock] for documentation.
+	// See the [sync::Mutex] for documentation.
 	fn tryLock(self): bool {
 		old := self.state
 		if old&(mutexLocked|mutexStarving) != 0 {
@@ -184,7 +184,7 @@ impl mutex {
 	}
 
 	// Unlocks the mutex.
-	// See the [sync::Mutex.Unlock] for documentation.
+	// See the [sync::Mutex] for documentation.
 	fn unlock(self) {
 		// Fast path: drop lock bit.
 		new := atomicAdd(self.state, -mutexLocked, atomicSeqCst)

std/sync/once_test.jule

@@ -0,0 +1,39 @@
+// Copyright 2024 The Jule Programming Language.
+// Use of this source code is governed by a BSD 3-Clause
+// license that can be found in the LICENSE file.
+
+use "std/sync/atomic"
+use "std/testing"
+
+type one: int
+
+impl one {
+	fn Increment(mut self) {
+		self++
+	}
+}
+
+fn run(t: &testing::T, once: &Once, mut o: &one, mut c: &int) {
+	once.Do(fn() { o.Increment() })
+	if *o != 1 {
+		t.Errorf("once failed inside run: {} is not 1", *o)
+	}
+	atomic::Add(*c, 1, atomic::SeqCst)
+}
+
+#test
+fn testOnce(t: &testing::T) {
+	mut o := new(one)
+	mut once := new(Once)
+	mut c := new(int)
+	const N = 10
+	mut i := 0
+	for i < N; i++ {
+		co run(t, once, o, c)
+	}
+	for atomic::Load(*c, atomic::SeqCst) != N {
+	}
+	if *o != 1 {
+		t.Errorf("once failed outside run: {} is not 1", *o)
+	}
+}