var utils = {
    buildRequest: buildRequest,
    makeRequest: makeRequest
};

module.exports = {
    getData: getData,
    buildRequest: buildRequest,
    makeRequest: makeRequest,
    utils: utils
};

function buildRequest(resource) {
    return 'request';
}

function getData(resource, callback) {
    var request = utils.buildRequest(resource);
    utils.makeRequest(request, callback);
}

function makeRequest(request, onCompleteFn) {
    // do some IO get some data or receive an error
    var someFakeData = {};
    onCompleteFn(someFakeData);
}

------

var assert = require('chai').assert;
var resources = require('./resources.js');
var sinon = require('sinon');


describe('resources.js', function() {
    describe('getData()', function() {
        it('calls makeRequest with a built request', function() {
            resources.utils.makeRequest = sinon.spy();
            var resource = 'a resource';
            var request = resources.buildRequest(resource);

            var callback = sinon.spy();
            resources.getData(resource, callback);
            assert.isTrue(
                resources.utils.makeRequest.withArgs(
                    request, callback).calledOnce
            );

        });
    });
});

-----

$ mocha *.spec.js


  resources.js
    getData()
      ✓ calls makeRequest with a built request


  1 passing (13ms)