Cool Trick For Unit Testing The Angular Controller

Almost always when writing unit tests for controller we need somehow to handle the fact that controller calls to some service/factory.

Lets look at following controller:

angular.module('siteApp')
        .controller('RegisterCtrl', function (
        $scope,
         auth,
         $location,
         $interval) {

            $scope.user = {};
            $scope.messages = [];


            var success = function(){
                $scope.messages.push({
                    type:'success',
                    text:'Congratulations,You are registered user!'
                });             
                $interval(function(){$location.path('/login')},6000,1)
            }, error =function(){
                $scope.messages.push({
                   type:'danger',
                   text:'error occurred during registration'
                });                
            };

            $scope.save = function(){
                auth.register($scope.user).then(success, error);         
            }

  });

The controller uses "auth" service and its "register" method, which sending a request.
We can mock the request with $httpBackend service which test if request is sended.

it('after clicking "save" some request should be sent', function () {
  initCtrl()
  $httpBackend.expectPOST('/api/register').respond(200, {});
  $scope.save();
  $httpBackend.flush();
});

Since we trying now to test the logic of the controller (not the service)- I think better practice is to mock the  service method and only test if it been called with proper parameters:

it('after clicking "save" auth.register should call', function () {

    initCtrl()
    spyOn(auth, 'register').andReturn($q.when()); 
    $scope.save();
    expect(auth.register).toHaveBeenCalledWith($scope.user);

    $scope.$digest();   //important!!!
    expect($scope.messages.length).toBe(1)


});

Notice that for testing the messages array you need 

  $scope.$digest(); 

statement for update the scope.

Hope you have fun reading...