diff --git a/tests/TestCase.php b/tests/TestCase.php
index 34838af..d83bd9b 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -274,7 +274,7 @@ abstract class TestCase extends BaseTestCase
 
         // Replace the publish and subscribe clients with a Mocked
         // factory lazy instance on boot.
-        $this->app->singleton(ReplicationInterface::class, function () {
+        $this->app->singleton(ReplicationInterface::class, function () use ($replicationDriver) {
             $client = config(
                 "websockets.replication.{$replicationDriver}.client",
                 \BeyondCode\LaravelWebSockets\PubSub\Drivers\LocalClient::class