diff --git a/tests/src/Functional/LoadTest.php b/tests/src/Functional/LoadTest.php
index db0f41edc534848e5fd25efe29500c884f7c92b2..2de25fa7344a4b0de6ee1012c2ac985d3663ac30 100644
--- a/tests/src/Functional/LoadTest.php
+++ b/tests/src/Functional/LoadTest.php
@@ -26,6 +26,13 @@ class LoadTest extends BrowserTestBase {
    */
   protected $user;
 
+  /**
+   * Set the default theme to use.
+   *
+   * @var \string
+   */
+  protected $defaultTheme = 'stark';
+
   /**
    * {@inheritdoc}
    */