Unit testing angularjs controller using Node.js, Gulp.js and Mocha

I am trying to unit test an angularjs controller using Node.js. I am using gulp.js and mocha to run the tests, via gulp-mocha.

This is what my gulpfile.js looks like right now:

(function () {

    var gulp = require('gulp');
    var mocha = require('gulp-mocha');

    gulp.task('default', function () {
        return gulp
            .src('Scripts/Tests/*.js', { read: false })
            .pipe(mocha({ 
                ui: 'tdd', 
                reporter: 'dot',
                globals: {
                    angular: require('./Scripts/angular.js')
                }
            }));
    });

})();

This is the code under test:

(function () {

    var application = angular.module('Main');

    application.controller('MainController', ['$scope', function ($scope) {

        $scope.isDisabled = function () {
            return true;
        };

    }]);

})();

And this is the test file itself:

(function () {

    var chai = require('chai');
    var assert = chai.assert;

    angular.module('Main', []);  // Create an empty module  
    require('../MainController.js');  // Fill the module with the controller

    suite('Main Controller', function () {

        test('isDisabled always true', function () {

            var controllerFactory = angular.injector.get('$controller');
            var controller  = controllerFactory('MainController', {
                'MainController': {}
            });

            var result = controller.isDisabled();
            assert.isTrue(result);
        });

    });

})();

I need to make angular a global in order for my test and the file I am testing to work. However, the call to require in gulpfile.js is giving me a Reference Error: window is not defined error. That makes sense, since I am running in Node.js.

What do I need to do to load up angular in Node.js?