karma-requirejs-exposure

Karma's plugin which allows to test private functional of AMD-modules

Contains:

Preprocessor, which looks through module content for @export %module_name% JSDoc notation and (if it exists) injects piece of code into module definition callback.
Client lib allows to get access to private variable and functions from spec.

Installation

Requires Karma 0.9+

To use this with karma, first you will need to install it with npm

npm install https://github.com/laboro/karma-exposure-preprocessor --save-dev

Next you need to create a configuration file using karma init

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['jasmine', 'requirejs-exposure', 'requirejs'],

    preprocessors: {
      '**/*.js': ['requirejs-exposure']
    },

    files: [
      '*.js'
    ],

    plugins: [
      'karma-requirejs',
      'karma-jasmine',
      'karma-phantomjs-launcher',
      'karma-requirejs-exposure'
    ]
  });
};

Example

Let's take some/module.js module:

define(function () {
  var foo = {};
  foo.do = function () {};

  /**
   * @export some/module
   */
  return {
    doSomething: function () {
      foo.do();
    }
  };
});

And try to test private foo object. Jasmine spec for that module will be:

define(['some/module', 'requirejs-exposure'],
function(module, requirejsExposure) {
  // get exposure instance for tested module
  var exposure = requirejsExposure.disclose('some/module');

  describe('some/module', function () {
    var foo;
    // save original value of foo variable
    exposure.backup('foo');

    beforeEach(function () {
      // create mock object with stub method 'do'
      foo = jasmine.createSpyObj('foo', ['do']);
      // before each test, pass it off instead of original
      exposure.substitute('foo').by(foo);
    });
    afterEach(function () {
        // after each test restore original value of foo
        exposure.recover('foo');
    });

    it('check doSomething() method', function() {
      // private foo object is successfully replaced by mock
      expect(exposure.retrieve('foo')).toBe(foo);
      // mean time, original object is safe
      expect(exposure.retrieve('foo')).not.toBe(exposure.original('foo'));

      module.doSomething();

      // stub method of mock object has been called
      expect(foo.do).toHaveBeenCalled();
      // this is the same as previous assertion
      expect(exposure.retrieve('foo')).toHaveBeenCalled();
      //but original method never touched
      expect(exposure.original('foo')).not.toHaveBeenCalled();
    });
  });
});

Also karma-requirejs-exposure plugin very useful for mocking depended on modules. It works the same way for any named argument of define() callback (as well require() and requirejs()), private variable or function.

laboro/karma-requirejs-exposure

karma-requirejs-exposure

Installation

Example