Sinon JS "Attempted to wrap ajax which is already wrapped"

Question

I got the above error message when I ran my test. Below is my code (I'm using Backbone JS and Jasmine for testing). Does anyone know why this happens?

$(function() {
  describe("Category", function() {
     beforeEach(function() {
      category = new Category;
      sinon.spy(jQuery, "ajax");
     }

     it("should fetch notes", function() {
      category.set({code: 123});
      category.fetchNotes();
      expect(category.trigger).toHaveBeenCalled();
     }
  })
}

score 99 · Accepted Answer · answered Jan 11 '12 at 20:21

99

You have to remove the spy after every test. Take a look at the example from the sinon docs:

{
    setUp: function () {
        sinon.spy(jQuery, "ajax");
    },

    tearDown: function () {
        jQuery.ajax.restore(); // Unwraps the spy
    },

    "test should inspect jQuery.getJSON's usage of jQuery.ajax": function () {
        jQuery.getJSON("/some/resource");

        assert(jQuery.ajax.calledOnce);
        assertEquals("/some/resource", jQuery.ajax.getCall(0).args[0].url);
        assertEquals("json", jQuery.ajax.getCall(0).args[0].dataType);
    }
}

So in your jasmine test should look like this:

$(function() {
  describe("Category", function() {
     beforeEach(function() {
      category = new Category;
      sinon.spy(jQuery, "ajax");
     }

     afterEach(function () {
        jQuery.ajax.restore();
     });

     it("should fetch notes", function() {
      category.set({code: 123});
      category.fetchNotes();
      expect(category.trigger).toHaveBeenCalled();
     }
  })
}

answered Jan 11 '12 at 20:21

Andreas Köberle

106,652
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In one of my trials, I had an afterEach block too but it didn't solve the problem. Could it be because I put the afterEeach after all the tests instead of right after beforeEach? – trivektor Jan 11 '12 at 20:26
I think so, cause `beforeEach`and `afterEach` are function calls just as your tests. So calling `afterEach` after all your tests will have no effect. – Andreas Köberle Jan 11 '12 at 20:30
process.exit.restore(); ... nice – danday74 Apr 06 '17 at 04:07
2019...Juste add into describe block this function : afterEach(function () { jQuery.ajax.restore(); }); or afterEach(function () { $.ajax.restore(); }); It depend your import about jQuery. often we writed "import * as $ from ..." – Vifier Lockla Aug 22 '19 at 20:05
Was still facing this issue, thanks to my colleague who left this hole in his test cases. worked after closing it. – Tukaram Bhosale Mar 10 '21 at 22:00

score 9 · Answer 2 · answered Oct 21 '15 at 03:25

9

What you need in the very beginning is:

  before ->
    sandbox = sinon.sandbox.create()

  afterEach ->
    sandbox.restore()

Then call something like:

windowSpy = sandbox.spy windowService, 'scroll'

Please notice that I use coffee script.

answered Oct 21 '15 at 03:25

Winters Huang

761
10
18

9

Unless open ended or unspecified, answers should be in the language the question is in. – Justin Johnson Jan 09 '17 at 08:35
@JustinJohnson I don't think there is any misunderstanding between JS and coffee script. BTW, they are the SAME language. – Winters Huang Jan 10 '17 at 04:39
6

Your experience and that of the questioner are not the same, and you shouldn't assume that they are. CoffeeScript adds syntactic sugar to JavaScript (which you used here), so they are *not* the same thing. – Justin Johnson Jan 11 '17 at 05:04
1

`afterEach` and calling `sandbox.restore()` plus one – Connor Leech Dec 21 '18 at 19:43

Sinon JS "Attempted to wrap ajax which is already wrapped"

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