diff --git a/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
index d6ef176..6a093de 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
@@ -89,7 +89,7 @@
    *
    * @var boolean
    */
-  public $verbose = FALSE;
+  public $verbose;
 
   /**
    * Incrementing identifier for verbose output filenames.
@@ -724,7 +724,7 @@ public function run(array $methods = array()) {
     $simpletest_config = \Drupal::config('simpletest.settings');
 
     $class = get_class($this);
-    if ($this->verbose || $simpletest_config->get('verbose')) {
+    if (!empty($this->verbose) || (!isset($this->verbose) && $simpletest_config->get('verbose'))) {
       // Initialize verbose debugging.
       $this->verbose = TRUE;
       $this->verboseDirectory = PublicStream::basePath() . '/simpletest/verbose';