gistfile1.js

var sinon = require('sinon');
var hottap = require('hotttap');

var foo = function(url) {
  var resp = hottap.hottap(url);
  return resp;
};

foo('http://somewhere/over/the/rainbow');


and test:

describe('foo', function() {
  it('should yank urls', function() {
    var hottap = sinon.mock(hottap, 'hottap', function(url) {
      return 'some silly json blob goes here';
    });
    foo('http://somewhere/else/over/the/rainbow');
    // asserts and such
  });
});