diff --git a/src/queueManager.ts b/src/queueManager.ts
index 467e7ef..73f4956 100644
--- a/src/queueManager.ts
+++ b/src/queueManager.ts
@@ -14,8 +14,8 @@ class QueueManager {
     private browser: Browser | null;
     private queue: QueueItem[];
 
-    constructor() {
-        this.browser = null;
+    constructor(browser: Browser | null = null) {
+        this.browser = browser;
         this.queue = [];
     }