Makes event timer stop idempotent

internal/event_timer.go

@@ -10,6 +10,7 @@ type EventTimer struct {
 	timer *time.Timer
 	done  chan struct{}
 	wg    sync.WaitGroup
+	once  sync.Once
 }
 
 func NewEventTimer(task func()) *EventTimer {
@@ -45,7 +46,10 @@ func (t *EventTimer) Stop() {
 		return
 	}
 
-	close(t.done)
+	t.once.Do(func() {
+		close(t.done)
+	})
+
 	t.wg.Wait()
 }
 

internal/event_timer_test.go

@@ -0,0 +1,27 @@
+// Copyright (c) quickfixengine.org  All rights reserved.
+//
+// This file may be distributed under the terms of the quickfixengine.org
+// license as defined by quickfixengine.org and appearing in the file
+// LICENSE included in the packaging of this file.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING
+// THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE.
+//
+// See http://www.quickfixengine.org/LICENSE for licensing information.
+//
+// Contact [email protected] if any conditions of this licensing
+// are not clear to you.
+
+package internal
+
+import (
+	"testing"
+)
+
+func TestEventTimer_Stop_idempotent(*testing.T) {
+	t := NewEventTimer(func() {})
+
+	t.Stop()
+	t.Stop()
+}