diff --git a/tests/FluentDOM/TestCase.php b/tests/FluentDOM/TestCase.php
index 3e8c9f7f..53bdaf87 100644
--- a/tests/FluentDOM/TestCase.php
+++ b/tests/FluentDOM/TestCase.php
@@ -4,9 +4,9 @@
   require_once(__DIR__.'/../../vendor/autoload.php');
 
   if (!class_exists('PHPUnit_Framework_TestCase')) {
-     class PHPUnit_TestCase extends \PHPUnit\Framework\TestCase {}
+     abstract class PHPUnit_TestCase extends \PHPUnit\Framework\TestCase {}
   } else {
-     class PHPUnit_TestCase extends \PHPUnit_Framework_TestCase {}
+     abstract class PHPUnit_TestCase extends \PHPUnit_Framework_TestCase {}
   }
 
   abstract class TestCase extends PHPUnit_TestCase {