diff --git a/test/simple/test-fs-write-file.js b/test/simple/test-fs-write-file.js
index 32ae96155eb..ce09d26b164 100644
--- a/test/simple/test-fs-write-file.js
+++ b/test/simple/test-fs-write-file.js
@@ -31,7 +31,7 @@ filename2 = join(fixturesDir, 'test2.txt');
 buf = new Buffer(s, 'utf8');
 error('writing to ' + filename2);
 
-fs.writeFile(filename2, s, function (e) {
+fs.writeFile(filename2, buf, function (e) {
   if (e) throw e;
 
   ncallbacks++;