diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 7e71112c7b2349a9e281a99367a5201c3318cf4e..c55247203d549c40a49f2233f0dcc5887e3c5171 100644
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -522,7 +522,7 @@ function simpletest_script_execute_batch($test_classes) {
       $test_class = array_shift($test_classes);
       // Process phpunit tests immediately since they are fast and we don't need
       // to fork for them.
-      if (is_subclass_of($test_class, 'Drupal\Tests\UnitTestCase')) {
+      if (is_subclass_of($test_class, '\PHPUnit_Framework_TestCase')) {
         simpletest_script_run_phpunit($test_id, $test_class);
         continue;
       }
@@ -811,7 +811,7 @@ function simpletest_script_get_test_list() {
         else {
           foreach ($matches[1] as $class_name) {
             $namespace_class = $namespace . '\\' . $class_name;
-            if (is_subclass_of($namespace_class, '\Drupal\simpletest\TestBase') || is_subclass_of($namespace_class, '\Drupal\Tests\UnitTestCase')) {
+            if (is_subclass_of($namespace_class, '\Drupal\simpletest\TestBase') || is_subclass_of($namespace_class, '\PHPUnit_Framework_TestCase')) {
               $test_list[] = $namespace_class;
             }
           }