Angular Testing Example Fail

Being new to JS unit testing and Angular testing in particular, I tried writing my own tests with Jasmine and Karma. After numerous failed attempts at writing my own tests, I decided to step back and check whether everything is working properly, so I copied the example controller and its tests from the Angular Documentation on Unit testing into my project and I am unable to get even that to work.. I feel like a complete idiot that can't even get the copy-pasted code to work..

So here is the controller that I have initialized in the step1Ctrl.js file:

Module is initialized in another file.

var mainApp = angular.module("mainApp");

mainApp.controller('PasswordController', function PasswordController($scope) {   $scope.password = '';   $scope.grade = function() {
    var size = $scope.password.length;
    if (size > 8) {
      $scope.strength = 'strong';
    } else if (size > 3) {
      $scope.strength = 'medium';
    } else {
      $scope.strength = 'weak';
    }   }; });

And here's are the tests that live inside step1Ctrl.spec.js:

describe('PasswordController', function() {
  beforeEach(module('mainApp'));

  var $controller;

  beforeEach(inject(function(_$controller_){
    // The injector unwraps the underscores (_) from around the parameter names when matching
    $controller = _$controller_;
  }));

  describe('$scope.grade', function() {
    var $scope, controller;

    beforeEach(function() {
      $scope = {};
      controller = $controller('PasswordController', { $scope: $scope });
    });

    it('sets the strength to "strong" if the password length is >8 chars', function() {
      $scope.password = 'longerthaneightchars';
      $scope.grade();
      expect($scope.strength).toEqual('strong');
    });

    it('sets the strength to "weak" if the password length <3 chars', function() {
      $scope.password = 'a';
      $scope.grade();
      expect($scope.strength).toEqual('weak');
    });
  });
});

Literally copy-pasted from the documentation.

So the error that I get upon running the tests is:

TypeError: undefined is not a constructor (evaluating '$controller('PasswordController', { $scope: $scope })')

Which tells me that the $controller function in the second beforeEach is failing, as $controller is undefined. So it looks like the first beforeEach doesn't run, or it does but an undefined value gets injected with the inject function.

I am also using browserify, if that matters.

Here is my karma.conf.js, if that helps, as well:

module.exports = function(config) {
  config.set({

    basePath: '',

    frameworks: ['browserify', 'jasmine'],

    files: [
        'http://ift.tt/1KSqWqC',
        'http://ift.tt/1NgogVP',
        'http://ift.tt/1KSqU1W',
        'test/unit/**/*.js'
    ],

    exclude: [
    ],

    preprocessors: {
        'app/main.js': ['browserify']
    },

    reporters: ['progress'],

    port: 9876,

    colors: true,

    logLevel: config.LOG_INFO,

    autoWatch: true,

    browsers: ['PhantomJS'],

    browserify: {
        debug: true,
        transform: []
    },

    plugins: [
        'karma-phantomjs-launcher', 'karma-jasmine', 'karma-bro'
    ],

    singleRun: false,


    concurrency: Infinity
    });
};