diff --git a/core/modules/system/tests/src/FunctionalJavascript/ModuleFilterTest.php b/core/modules/system/tests/src/FunctionalJavascript/ModuleFilterTest.php
index 9abb9772bc..1bffcd38f0 100644
--- a/core/modules/system/tests/src/FunctionalJavascript/ModuleFilterTest.php
+++ b/core/modules/system/tests/src/FunctionalJavascript/ModuleFilterTest.php
@@ -14,7 +14,12 @@ class ModuleFilterTest extends WebDriverTestBase {
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['user', 'system'];
+  protected static $modules = ['user', 'system'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
 
   /**
    * {@inheritdoc}