remove annoying "double callback" warning

i’d rather have an error thrown than console.warn('double callback!')

[MattCain]

I’m getting the double callback message when testing (with mocha) the GET routes of my API:

it('should get the account metadata', function(done) {
    request.get('https://***/api/user/1')
    .end(function(e, res) {
        expect(res.body).to.have.property('_id');
        expect(res.body).to.have.property('created');
        done();
    });
});

None of my POST/PUT/DELETE requests are getting it and they’re in the same format. What’s causing it in this case?

[vizath]

I cannot reproduce my use case on 3.3.1 🎉