commit 622e648fb1538e1a55aad1e61d684591ab3c5c94
Author: Tom Hughes <tom@compton.nu>
Date:   Fri Aug 23 08:46:34 2019 +0100

    Pass required callback to writeFile

diff --git a/test/tester.js b/test/tester.js
index 23a5843..be6c14c 100644
--- a/test/tester.js
+++ b/test/tester.js
@@ -358,5 +358,5 @@ function cb_helper(name, file, done){
 }
 
 function complete_helper(path){
-  fs.writeFile(__dirname + path, (new Date).getTime() + "\n");
+  fs.writeFile(__dirname + path, (new Date).getTime() + "\n", function (err) {});
 }