diff --git a/test/asyncworker-persistent.cc b/test/asyncworker-persistent.cc
index b8befa583..87717e1ae 100644
--- a/test/asyncworker-persistent.cc
+++ b/test/asyncworker-persistent.cc
@@ -7,6 +7,8 @@
 
 using namespace Napi;
 
+namespace {
+
 class PersistentTestWorker : public AsyncWorker {
 public:
   static void DoWork(const CallbackInfo& info) {
@@ -79,6 +81,8 @@ class PersistentTestWorker : public AsyncWorker {
   bool _succeed;
 };
 
+}  // end of anonymous namespace
+
 Object InitPersistentAsyncWorker(Env env) {
   Object exports = Object::New(env);
   exports["doWork"] = Function::New(env, PersistentTestWorker::DoWork);