How to avoid timeouts in mocha testcases?

Here I am attaching my code, I am passing done callback and using supertest for request. Since I am using assert/expect in my testcase inside request.end block why I need to worry about timeout? What is mistake I am making here.

it('should get battle results ', function(done) { request(url) .post('/compare?vf_id='+vf_id) .set('access_token',access_token) .send(battleInstance) .end(function(err, res){ // why need timeout if (err) return done(err); console.log(JSON.stringify(res.body)); expect(res.body.status).to.deep.equal('SUCCESS'); done(); }); });

Testcase results following response: Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.

If I am running my testcases with mocha command then its show this error while If I am running test mocha --timeout 15000 then testcase is passing correctly. But I want to avoid timeout, How can I do that?