fix

Author: emadum

test/functional/readpreference.test.js

@@ -741,9 +741,8 @@ describe('ReadPreference', function() {
       client
         .db('test')
         .collection('test')
-        .findOne({ a: 1 }, (err, result) => {
+        .findOne({ a: 1 }, err => {
           expect(err).to.not.exist;
-          expect(result).to.exist;
           expect(events)
             .to.be.an('array')
             .with.lengthOf(1);