diff --git a/tests/unit/bootstrap.php b/tests/unit/bootstrap.php
index e55059f69f9265d81aa3a4afa8c679633a5a6ad9..4d5049daa7fc21fd24b5901aca86f1137e8f0781 100644
--- a/tests/unit/bootstrap.php
+++ b/tests/unit/bootstrap.php
@@ -21,3 +21,9 @@ if ( getenv( 'ABSPATH' ) !== false ) {
 
 WP_Mock::setUsePatchwork( true );
 WP_Mock::bootstrap();
+
+if (!function_exists('wp_kses_post')) {
+    function wp_kses_post($data) {
+        return htmlspecialchars($data, ENT_QUOTES, 'UTF-8');
+    }
+}