sync/waitgroup: backport from master

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

sync/waitgroup_test.go

@@ -0,0 +1,37 @@
+package sync
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestWaitGroupContext(t *testing.T) {
+	wg := NewWaitGroup()
+	_ = t
+	wg.Add(1)
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}
+
+func TestWaitGroupReuse(t *testing.T) {
+	wg := NewWaitGroup()
+	defer func() {
+		if wg.Waiters() != 0 {
+			t.Fatal("lost goroutines")
+		}
+	}()
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel = context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}