diff --git a/sites/example.settings.local.php b/sites/example.settings.local.php
index 6bf2fd705e44733146516b04fe806d7d769c2c6b..7859fe5021951e9a393204ae347e5a690f440f9b 100644
--- a/sites/example.settings.local.php
+++ b/sites/example.settings.local.php
@@ -37,6 +37,15 @@
  */
 $settings['cache']['bins']['render'] = 'cache.backend.null';
 
+/**
+ * Allow test modules and themes to be installed.
+ *
+ * Drupal ignores test modules and themes by default for performance reasons.
+ * During development it can be useful to install test extensions for debugging
+ * purposes.
+ */
+$settings['extension_discovery_scan_tests'] = TRUE;
+
 /**
  * Enable access to rebuild.php.
  *