diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index ae489e1c772ec43b2932e0f9ca6de09d31316290..58f45ae9451f60f1a0930659dc73dfe96b4c8a90 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -668,7 +668,10 @@ function simpletest_script_get_test_list() {
         }
         else {
           foreach ($matches[1] as $class_name) {
-            $test_list[] = $namespace . '\\' . $class_name;
+            $namespace_class = $namespace . '\\' . $class_name;
+            if (is_subclass_of($namespace_class, '\Drupal\simpletest\TestBase') || is_subclass_of($namespace_class, '\Drupal\Tests\UnitTestCase')) {
+              $test_list[] = $namespace_class;
+            }
           }
         }
       }