diff --git a/src/Mustache/Engine.php b/src/Mustache/Engine.php
index 94ea124..6f4afd6 100644
--- a/src/Mustache/Engine.php
+++ b/src/Mustache/Engine.php
@@ -566,6 +566,8 @@ class Mustache_Engine
      *
      * @param string $fileName
      * @param string $source
+     *
+     * @codeCoverageIgnore
      */
     private function writeCacheFile($fileName, $source)
     {