diff --git a/core/tests/Drupal/Tests/ComposerIntegrationTest.php b/core/tests/Drupal/Tests/ComposerIntegrationTest.php
index e24195b..1527f18 100644
--- a/core/tests/Drupal/Tests/ComposerIntegrationTest.php
+++ b/core/tests/Drupal/Tests/ComposerIntegrationTest.php
@@ -82,7 +82,7 @@ public function testAllModulesReplaced() {
 
     $module_names = [];
     foreach ($folders as $file_name) {
-      if ($file_name !== '.' && $file_name !== '..' && is_dir($file_name)) {
+      if ($file_name !== '.' && $file_name !== '..' && is_dir($this->root . '/core/modules/' . $file_name)) {
         $module_names[] = $file_name;
       }
     }