diff --git a/lib/ClientManager.js b/lib/ClientManager.js
index 65686f1..9c62d03 100644
--- a/lib/ClientManager.js
+++ b/lib/ClientManager.js
@@ -11,6 +11,8 @@ class ClientManager {
     constructor(opt) {
         this.opt = opt || {};
 
+        this.opt.tokens = this.opt.tokens || {};
+
         // id -> client instance
         this.clients = new Map();
 
diff --git a/package.json b/package.json
index 0693b8d..c166166 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
     "ws": "5.1.1"
   },
   "scripts": {
-    "test": "mocha --check-leaks --require esm './**/*.test.js'",
+    "test": "mocha --check-leaks --require esm ./**/*.test.js",
     "start": "./bin/server",
     "dev": "node-dev bin/server --port 3000"
   }