Expected a spy, but got Function

Question

I am trying to implement a test (1) for this module (2).
My purpose is to check if the collection is fetched when a particular event is triggered.
As you can see from my comment in (2) I get the message Error: Expected a spy, but got Function.
The module works but the test fails. any ideas?

(1)

// jasmine test module

describe('When onGivePoints is fired', function () {
    beforeEach(function () {
        spyOn(this.view.collection, 'restartPolling').andCallThrough();
        app.vent.trigger('onGivePoints');
    });
    it('the board collection should be fetched', function () {
        expect(this.view.collection.restartPolling).toHaveBeenCalled();
       // Error: Expected a spy, but got Function.
    });
});

(2)

// model view module
return Marionette.CompositeView.extend({
    initialize: function () {
        this.collection = new UserBoardCollection();
        this.collection.startPolling();
        app.vent.on('onGivePoints', this.collection.restartPolling);
    },
    // other code
});

there's not enough code to see what's going on. please include more than just the individual functions - include the object definition that the functions belong to, and the code that instantiates the objects, at least. — Derick Bailey, Aug 21 '12 at 12:52
@DerickBailey thanks for your time. I updated my question with mode code. — Lorraine Bernard, Aug 21 '12 at 14:28
I use QUnit rather than Jasmine, but shouldn't your call to app.vent.trigger be in the "it" method rather than beforeEach? — codemonkey, Aug 21 '12 at 14:53
@codemonkey, @DerickBailey, actually I got a different error: `Expected a spy, but got Function`. I updated my question. — Lorraine Bernard, Aug 21 '12 at 14:59

antonjs · Accepted Answer · 2012-09-13T15:30:46.367

53

You need to get into the actual method, which in this case is on the prototype.

describe('When onGivePoints is fired', function () {
    beforeEach(function () {
        spyOn(UsersBoardCollection.prototype, 'restartPolling').andCallThrough();
        app.vent.trigger('onGivePoints');
    });
    it('the board collection should be fetched', function () {
        expect(UsersBoardCollection.prototype.restartPolling).toHaveBeenCalled();
    });
});

Spying on the prototype is a nice trick you can use when you can't get to the actual instance you want to spy on.

edited Sep 13 '12 at 15:30

answered Aug 21 '12 at 15:18

antonjs

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if the function does not exist on the prototype, and is a function inside a React class, is this expected to work? – zero_cool Apr 19 '18 at 18:55

score 4 · Answer 2 · edited Sep 23 '16 at 00:31

4

I was also getting the same issue but I resolved it by passing an argument in the function call. Then you have to write your test case like this in the it

var data = {name:"test"}
spyOn(UsersBoardCollection.prototype, "restartPolling").and.callThrough();
UsersBoardCollection.prototype.restartPolling(data);
expect(UsersBoardCollection.prototype.restartPolling).toHaveBeenCalled();

edited Sep 23 '16 at 00:31

Fengyang Wang

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answered Dec 17 '15 at 05:07

Tabish

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Why this prototype? – Rebai Ahmed May 19 '22 at 09:01
It's mentioned in the official docs? – Rebai Ahmed May 19 '22 at 09:03

score 0 · Answer 3 · answered Sep 18 '16 at 23:19

0

I had this bug because I had two versions of sinon loaded, or possibly i wasn't initialising sinon-jasmine correctly. When I explicitly loaded sinon and then sinon jasmine in my spec setup, it started running correctly.

answered Sep 18 '16 at 23:19

bnolan

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Expected a spy, but got Function

3 Answers3

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