diff --git a/tests/LessSourceTest.php b/tests/LessSourceTest.php
index 16c0715..4a22b29 100644
--- a/tests/LessSourceTest.php
+++ b/tests/LessSourceTest.php
@@ -4,6 +4,9 @@ namespace Minify\Test;
 
 use Minify_HTML_Helper;
 
+/**
+ * @requires php < 7.3
+ */
 class LessSourceTest extends TestCase
 {
     public function setUp()