How to create unit-testing for array function in AngularJS with Jasmine

Question

I have xf array: var xf = []; And I have a function is a element in this array and a function to use it:

$scope.checkEmailValid = function () {
  var result = false;
  Iif (xf.validateEmail($scope.email, '256')) {
    result = true;
  }
  return result;
};

xf.validateUsername = function (sText) {
  var isValid = false;
  do {
    //Check for valid string.
    isValid = typeof sText === 'string';
    if (!isValid) {
      break;
    }
    //Check that each special character does not exist in string.
    for (var i = 0; i < sText.length; i++) {
      if (xf.SPECIAL_CHARS.indexOf(sText.charAt(i)) !== -1) {
        isValid = false;
        break;
      }
    }
    if (!isValid) {
      break;
    }
  } while (false);
  return isValid;
};

But when I run my spec:

it ('checkEmail', function(){
  $controller('MyCtrl', { $scope: $scope });
  xf.validateUsername();
  spyOn(window,xf.validateUsername).and.callThrough();
});

It makes an error:

xf.validateUsername is not a function

How can I cover it?

Answer 1

The xf variable is not acessible from the outside of the controller's scope (i.e. not accessible in the unit test files).

You must've done the following thing:

angular
  .module('myModule')
  .controller(function ($scope) {
    var xf = [];
    // etc.
  });

You could attach the xf variable to the MyController instance once Angular instantiates it:

angular
  .module('myModule')
  .controller(function ($scope) {
    this.xf = [];
    // etc.
  });

But that's not really a clean way of doing it. A better way (in my opinion) would be to create a factory:

angular
  .module('myModule')
  .factory('xfService', function () {
    var xf = [];

    function validateUsername(text) {
      // etc.
    }

    function get() {
      return xf;
    }

    return {
      get: get,
      validateUsername: validateUsername
    };
  });

Now, you can inject the factory in your controller to use xf:

angular
  .module('myModule')
  .controller(function ($scope, xfService) {
    // somewhere
    var isValid = xfService.validateEmail($scope.email, '256');
    // to get the values in the array
    var values = xfService.get();
  });

Finally, for the unit tests, it becomes really easy to test the validateEmail method.

describe('Unit tests - xfService', function () {
  var xfService;
  beforeEach(angular.module('myModule'));
  beforeEach(angular.inject(function (_xfService_) {
      xfService = _xfService_;
    });
  });

  describe('xfService.validateUsername', function () {
    it('should return a boolean value', function () {
      // for example
      expect(typeof xfService.validateUsername('test')).toBe('boolean');
    });
    // add more unit tests to check that the method works as expected
  });
});

You'll need to add the angular-mocks file to the Karma config.

Thanks to Paul Podlech and Claies for the hints in the comments/answers.