fs.writeSync should return bytes written

lib/fs.js

@@ -221,7 +221,7 @@ fs.writeSync = function (fd, buffer, offset, length, position) {
     length = buffer.length;
   }
 
-  binding.write(fd, buffer, offset, length, position);
+  return binding.write(fd, buffer, offset, length, position);
 };
 
 fs.rename = function (oldPath, newPath, callback) {

test/simple/test-fs-write-sync.js

@@ -11,7 +11,8 @@ var fd = fs.openSync(fn, 'w');
 fs.writeSync(fd, foo);
 
 bar = 'bár'
-fs.writeSync(fd, new Buffer(bar), 0, Buffer.byteLength(bar));
+written = fs.writeSync(fd, new Buffer(bar), 0, Buffer.byteLength(bar));
+assert.ok(written > 3);
 fs.closeSync(fd);
 
 assert.equal(fs.readFileSync(fn), 'foobár');