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testingbackbone.jsjasminesinon

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


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();
     }
  })
}

Solution

  • 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();
         }
      })
    }