diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container14.php b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container14.php
index 593be9c399363..a6eb33198d4fc 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container14.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container14.php
@@ -4,8 +4,10 @@
 
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 
-class ProjectServiceContainer extends ContainerBuilder
-{
+if (!class_exists('Container14\ProjectServiceContainer')) {
+    class ProjectServiceContainer extends ContainerBuilder
+    {
+    }
 }
 
 return new ProjectServiceContainer();