AngularJs unit test - Check if "Init" function was called

Question

I'm using jasmine as testframework and I've the following Controller I want to test. And I allways have a Init() function where I place my initialization calls for this Controller.

Now I want to test if the Init function was called when the controller was initialized.

function UnitTestsCtrl() {
   var that = this;
   this.Init();
}

UnitTestsCtrl.prototype.Init = function() {
    var that = this;
    //Some more Stuff
}

angular.module("unitTestsCtrl", [])
       .controller("unitTestsCtrl", UnitTestsCtrl);

But I was not able to check if the Init function was called on controller creation. I know my example doesn't work because the spy is set on the Init function after creation.

describe('Tests Controller: "UnitTestsCtrl"', function() {
var ctrl;

   beforeEach(function() {
         module('app.main');
         inject(function ($controller) {
            ctrl = $controller('unitTestsCtrl', {});
         });
   });

   it('Init was called on Controller initialize', function () {
       //thats not working
       spyOn(ctrl, 'Init');
       expect(ctrl.Init).toHaveBeenCalled();
   });
});

Solution:

Create the spy on the Original Prototype in the beforeEach function

 beforeEach(function() {
     module('app.main');

     spyOn(UnitTestsCtrl.prototype, 'Init');

     inject(function ($controller) {
        ctrl = $controller('unitTestsCtrl', {});
     });
 });

 it('Init was called on Controller initialize', function () {
        expect(ctrl.Init).toHaveBeenCalled();
 });

PSL · Accepted Answer · 2015-02-08 16:32:03Z

3

The way it is, you cannot and you really do not need to as well. The reason you cannot is because you are calling init() on the controller constructor, i.e on instantiation, which happens when you call $controller service to instantiate the controller in your test. So you are setting up spy too late. You probably do not need to, because if the controller is instantiated init method would have been called for sure. But how ever if you are making any specific service/dependency calls inside init, you can spy on those mocks and set up expectations.

Your expectation says: Service Call executed so create a spy for that service and set up expectation.

example:

   var myService = jasmine.createSpyObj('myService', ['someCall']);
   myService.someCall.and.returnValue($q.when(someObj));
   //...


  ctrl = $controller('unitTestsCtrl', {'myService':myService});

and set the expectation on the method someCall of myService.

 expect(myService.someCall).toHaveBeenCalled();

If you really want to spy on init, then you would need to have access to UnitTestsCtrl constructor in the spec and you would need to set spy on its prototype method init before instantiating.

edited Feb 8, 2015 at 16:32

answered Feb 8, 2015 at 16:12

PSL

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5 Comments

squadwuschel Over a year ago

I thought I can test if I have forgotten to call the Init() method on controller initialize - that I can test the call directly thats no problem I know.

PSL Over a year ago

@squadwuschel Your expectation says Service Call executed right? So spy on that. You are actually into a chicken <->egg situation since the call to init is made on the controller instance by the controller on instantiation.

squadwuschel Over a year ago

sry - I've edited my original post and changed the expectation to the right one (copy and paste mistake)

PSL Over a year ago

@squadwuschel If you really want to spy on init, then you would need to have access to UnitTestsCtrl constructor in the spec and you would need to set spy on its proto

squadwuschel Over a year ago

you helped me - I am calling a service inside my Init function and I am checking this service now and it works fine - thx

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