diff --git a/tests/Bootstrap.php b/tests/Bootstrap.php
index 589745a..0999d1c 100644
--- a/tests/Bootstrap.php
+++ b/tests/Bootstrap.php
@@ -5,6 +5,7 @@ defined('BASE') OR define('BASE', dirname($dir) . '/');
 
 require_once BASE . 'parsecsv.lib.php';
 
-if (class_exists('PHPUnit_Framework_TestCase')) {
+if (!class_exists('PHPUnit\Framework\TestCase')) {
+    // we run on an older PHPUnit version without namespaces.
     require_once __DIR__ . '/PHPUnit_Framework_TestCase.inc.php';
 }