diff --git a/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php b/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
index 7cbb905b..b6ff6669 100644
--- a/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
+++ b/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
@@ -4,6 +4,7 @@
 
 namespace DI\Test\UnitTest;
 
+use DI\Container;
 use DI\ContainerBuilder;
 use DI\ServiceLocator;
 use DI\Test\UnitTest\Fixtures\Singleton;
@@ -16,6 +17,8 @@
  */
 class ServiceLocatorTest extends TestCase
 {
+    private ?Container $container;
+
     public function setUp(): void
     {
         $containerBuilder = new ContainerBuilder();