Unit test Angular directive that accesses external element

Question

I have a custom directive that uses an attribute to specify another control that it modifies.

Directive definition object:

{
    restrict: 'E',
    templateUrl: 'myTemplate.html',
    scope: {
        targetId: '@'
    },
    controller: MyController,
    controllerAs: 'vm',
    bindToController: true
}

A function on the directive's controller modifies the contents of the target element (an input field):

function onSelection (value) {
    var $element = $('#' + vm.targetId);

    $element.val('calculated stuff');
    $element.trigger('input');
}

The unit tests (Jasmine/Karma/PhantomJS) currently append the element to the page. This works, but it seems like a code smell.

beforeEach(inject(function($rootScope, $compile) {
    var elementHtml = '<my-directive target-id="bar"></my-directive>' +
        '<input type="text" id="bar">';

    scope = $rootScope.$new();    
    angularElement = angular.element(elementHtml);
    angularElement.appendTo(document.body);  // HELP ME KILL THIS!
    element = $compile(angularElement)(scope);
    scope.$digest();
}));

afterEach(function () {
    angularElement.remove();  // HELP ME KILL THIS!
});

I've tried rewriting the controller function to avoid jQuery; this did not help.

How can I revise the directive or the tests to eliminate the appendTo/remove?

Answer 1

Your best bet is to migrate the directive to an attribute instead of an element. This removes the need for the target-id attribute and you don't need to hunt for the target element.

See http://jsfiddle.net/morloch/621rp33L/

Directive

angular.module('testApp', [])
  .directive('myDirective', function() {
    var targetElement;
    function MyController() {
      var vm = this;
      vm.onSelection = function() {
        targetElement.val('calculated stuff');
        targetElement.trigger('input');
      }
    }
    return {
      template: '<div></div>',
      restrict: 'A',
      scope: {
        targetId: '@'
      },
      link: function postLink(scope, element, attrs) {
        targetElement = element;
      },
      controller: MyController,
      controllerAs: 'vm',
      bindToController: true
    };
  });

Test

describe('Directive: myDirective', function() {
  // load the directive's module
  beforeEach(module('testApp'));

  var element, controller, scope;

  beforeEach(inject(function($rootScope, $compile) {
    scope = $rootScope.$new();
    element = angular.element('<input my-directive type="text" id="bar">');
    $compile(element)(scope);
    scope.$digest();
    controller = element.controller('myDirective');
  }));

  it('should have an empty val', inject(function() {
    expect(element.val()).toBe('');
  }));

  it('should have a calculated val after select', inject(function() {
    controller.onSelection();
    expect(element.val()).toBe('calculated stuff');
  }));
});