spyOn not working with js methods inside iron router action (Server Integration)

I'm trying to write test for a twilio application. My strategy is to make a http request to my server, like what twilio will do when receiving a phone call on one of my numbers, then analyze the xml retrieved from the server response.

I tried to stub Meteor.users.find. But, I didn't succeed. The call to Meteor.users.find is from a route action. I thought maybe there is a problem with spyOn and functions inside routes actions.

So, to investigate more in the problem. I decided to make the problem simpler. Here is the code: in /server/routes.js

ExpertTest = {
    foo: function () {
        console.log("called");
        return 4;
    }
};


allo = function () {
    var res = ExpertTest.foo();
    console.log(res);

};

Router.route('/call-api/intro', {
    where: "server",
    name: "Intro",
    action: function () {        
        ExpertTest.foo();

        this.response.writeHead(200, {'Content-Type': 'application/xml; charset=utf-8'});
        this.response.end();
    }
});

and in tests/jasmine/server/integration/IVRSpec.js

describe("With our IVR", function () {

    it("green test", function () {
        spyOn(ExpertTest, "foo").and.returnValue(50);

        allo();

        expect(ExpertTest.foo).toHaveBeenCalled();

    });




    it('red test', function() {
        spyOn(ExpertTest, "foo").and.returnValue(50);

        var callFirstResult = HTTP.get(baseUrl + '/call-api/intro');

        expect(ExpertTest.foo).toHaveBeenCalled();
    });

});

and here is the error in console:

jasmine-server-integration: 1 tests failed
With our IVR red test
Expected spy foo to have been called.
http://meteor💻app/tests/jasmine/server/integration/IVRSpec.js:81:32: Expected spy foo to have been called.

Did I do something wrong?

Can anyone help me?

Thank you very much