Requirejs-mock

About

requirejs-mock is a dependency injector for RequireJS modules. It allows you easily mock your module dependencies.

Installation

npm install requirejs-mock --save-dev

Usage example

var requirejs = require('requirejs');
var Injector = require('requirejs-mock').provide(requirejs);

describe('Test', function() {
  var injector;
  var mockA;
  var mockB;

  beforeEach(function() {
    // instantiate injector
    injector = Injector.create();

    // remapping to mock module (defined in separate file)
    injector.map('module/a', 'mock/a');

    // if you need to check smth on mockA
    mockA = injector.require('module/a');

    // use direct mock
    mockB = { someAction: jasmine.createSpy() };
    injector.mock('module/b', mockB);
  });

  // cleanup
  afterEach(function() {
    injector.destroy();
  });

  it('should work', function() {
    // require module C that depends on A and B
    var c = injector.require('module/c');
    c.doSmth();

    expect(mockB.someAction).toHaveBeenCalled();
    expect(mockA.someAction).toHaveBeenCalled();
  });
});

API

Instantiate injector

First of all you need to create an injector that will allow you to mock your modules dependencies.

// Get RequireJS instance
var requirejs = require('requirejs');

// Get Injector and provide RequireJS to it
var Injector = require('requirejs-mock').provide(requirejs);

beforeEach(function() {
  // instantiate injector
  var injector = Injector.create();

  // instantiate injector for non-default context (if such is configured for RequireJS)
  var otherInjector = Injector.create({ context: 'specs' });
});

Require

injector.require(name) - require the module. Module value will be returned.

var moduleA;
beforeEach(function() {
  moduleA = injector.require('module/a');
});

Mocks

mock()

Replaces module value with provided one.

injector.mock(name, value) - mock single module

injector.mock(Object(name: value)) - mock few modules

It's possible to provide any value (function, object, number, string, etc) as a result for the mocked module.

describe('Mocks', function() {
  beforeEach(function() {
    // provide a value that will be returned as a module
    injector.mock('module/a', valueA);
    injector.mock('module/b', valueB);

    injector.mock({
      'module/a': valueA,
      'module/b': valueB
    });
  });

  it('should work', function() {
    expect(injector.require('module/a')).toBe(valueA);
    expect(injector.require('module/b')).toBe(valueB);
  });
});

Notice: It's not possible to use injector.mock() and injector.map() for same module at a time. Notice: It's not possible to mock module that has been mocked before.

unmock()

injector.unmock(...name) - Remove mocks for one or few modules

injector.unmock() - Remove mocks for all modules mocked before

If you don't need a mock anymore it's possible to remove it. Original module value will be returned afterwards if you require the module.

// Unmock single module
injector.unmock('module/a');

// Unmock few modules at once
injector.unmock('module/a', 'module/b');

// Unmock all previiously mocked modules
injector.unmock();

Maps

Setup maps

injector.map(name, replacerName) - map module name to module replacerName

injector.map(Object(name, replacerName)) - map few modules to replacements

If you have a module mock in a separate file and just need to replace module with it - you should use module mapping. Notice that the replacer module should also be an AMD module.

beforeEach(function() {
  var injector = Injector.create();

  // remap module A to its mock
  injector.map('module/a', 'mock/a');
  injector.map('module/b', 'mock/b');

  // or as an object
  injector.map({
    'module/a': 'mock/a',
    'module/b': 'mock/b'
  });

  // load module C (that depends on A and B)
  var c = injector.require('module/c');
});

You could also provide different maps at the same time and restore original module value:

beforeEach(function() {
  var injector = Injector.create();

  // get original module value
  var aOrig = injector.require('module/a');

  // remap module/a => mock/a
  injector.map('module/a', 'mock/a');

  var a = injector.require('module/a');
  console.log(a === aOrig); // => false

  // remap module A => mock/a_one
  injector.map('module/a', 'mock/a_one');

  var aOne = injector.require('module/a');
  console.log(aOne === a); // => false
  console.log(aOne === aOrig); // => false

  // restore original module
  injector.unmap('module/a');
  console.log(
    injector.require('module/a') === aOrig
  ); // => true
});

Cleanup maps

injector.unmap(...name) - Remove mapping from module or few modules

injector.unmap() - Remove mappings from all previously mapped modules

If you need to get an original module instead of mapped mock - you could unmap the module.

// unmap single module
injector.unmap('module/a');

// unmap few modules at once
injector.unmap('module/a', 'module/b');

// unmap all modules mapped before
injector.unmap();

Notice: It's not possible to use injector.mock() and injector.map() for module at the same time.

Undefining a module

When you require() a module - RequireJS will automatically cache it with all dependencies. If you need to provide another dependencies mocks you should undefine module and then require() module again.

// Assume that you have module C that depends on module A and B
// module C is required and cached
var c = injector.require('module/c');

// provide mocks for dependencies
injector.mock('module/a', 123);
injector.mock('module/b', 456);

// undefine module C to get fresh dependencies afterwards
injector.undef('module/c');

// get module C with mocked dependencies
c = injector.require('module/c');

Notice: If you're using mock() module cache will be removed automatically for you and mocked module value will be returned afterwards, as expected.

// get original A value
var a = injector.require('module/a');

// mock module A
injector.mock('module/a', 123);
injector.require('module/a'); // => 123

Destroying the injector

You should always destroy injector to cleanup after it.

afterEach(function() {
  // cleanup
  injector.destroy();
});

RequireJS versions support

requirejs-mock supports RequireJS versions starting from 2.1.12. Previous versions are not supported.

Changelog

1.0.1 - Apr. 04, 2015

Provide additional documentation.

1.0.0 - Mar. 22, 2015

First stable release that supports all planned injector features.

[breaking] It's not possible to mock() and map() module at the same time. Previous behavior was not specified
Added ability to remove mocks and maps used before
Added ability to remove module from RequireJS cache

0.9.0 - Mar. 16, 2015

Initial release with basic capabilities

basecode/requirejs-mock