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Simple module for mocking required dependencies. Works with any testing suite.
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Simple module for mocking required dependencies. Works with any testing suite. (

Example Usage

Imagine your application uses the following module to onboard a user, in reaction to a recieved event. A service will require the module and call it, passing the event as a parameter. But, in the course of developing your application, you'd like to test the module in isolation from the rest of your code. The module depends on another module, 'my_db_lib'.

How can you test the module in isolation?

var db = require('my_db_lib');

module.exports = function onboardUser (event) {

  // we want to test this function's behavior, but need to isolate the behavior of the module apart from the behavior of it's dependency, the db. 

  db.User.findByEmail(, function (err, user) {
    if(err) throw err;

    user.onboarding = 'complete'; (err) { 
      if(err) throw err; 

MockRequire provides a simple means of allowing you to mock dependencies of any module you require(). Want to unit test your code without ever having to hit a database, even though your code is require-ing your datastore modules directly? MockRequire is exactly what you need.

The following example uses 'mocha' and 'should' to create a unit test for the module above. We also use 'mockrequire' to mock out our dependencies, parts of our module we don't care to isolate in our test.

var mockrequire = require('mockrequire');

var user = (function() {
  return {
    save: function (cb) {
      this.saved = true;

// instead of require()ing our handler directly, we can mockrequire() it and supply an object containing any child dependencies we would like to mock as well. Here we're mocking my_db_lib

var onboardUser = mockrequire('./handler', {
  'my_db_lib': {
    User: { 
      findByEmail: function (email, cb){
        cb(null, user);

// we create our unit tests with mocha

describe('userPaymentComplete()', function(){
  onboardUser({ email: '' });
  it('should set onboarding as \'complete\'', function() {'onboarding').equal('complete');
  it('should save user', function() {'saved').equal(true);

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