CODEWITHSUNDEEP
javascriptjasmine
Indradhanush Gupta
Indradhanush Gupta

Reputation: 4237

How to spy on the original function and not the dummy in Jasmine for javascript testing?

I looked at the other questions regarding spying on functions in Jasmine but I didn't get my doubt answered there. I intend to use andCallThrough to track my original function in my src script. This is what I have: 

describe("My Test to spy :", function() {                                       
    var mySpy = jasmine.createSpy(window, "login");                             
    beforeEach(function(){
        mySpy();
    });

    it("Expects login() will be called", function(){                               
      expect(mySpy).toHaveBeenCalled();                                         
    });    
});

So this test passes because its the spy that is being called right? Not the original implementation of the function. So if I use mySpy.andCallThrough() it gives an error. The docs are all about chaining objects and for methods. Nothing for functions. Need some help.

Upvotes: 2

Views: 2862

Answers (1)

Andreas Köberle
Andreas Köberle

Reputation: 110892

The problem is that you use createSpy instead of spyOn. createSpy will create a new spy so you can't use andCallThrough on it as there is no function to call. Using spyOn will replace an existing function with the spy and save the old function in the spy. So when you use andCallThrough it will call this old method.

You can use createSpy but then you have to pass a name and the original function: 

jasmine.createSpy('someName', window.login)

When you use `spyOn', you have to pass the an object holding the function and the name of the function:

jasmine.spyOn(window, 'login')

Upvotes: 4

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