How to do Dependency Injection in RequireJS?

example_code.js

define([], function () {

    return function HypotheticalHelperMethod() {
        doSomeOtherStuff();
    }

});


define(["helperMethod"], function (helperMethod) {

   MyClass = function () {
        this.init()
   }

   MyClass.prototype.init = function () {

        helperMethod(1, 2, 3);

   }

});

example_test.js

require(["helperMethod", "myClass"], function (helperMethod, myClass) {

    describe("MyClass tests", function () {

        it("calls `helperMethod` upon init", function () {

            // here i need to spyOn helperMethod, but if I set helperMethod
            // to a jasmime spy:
            helperMethod = jasmine.createSpy("helperMethod");
            // I've altered my reference, and MyClass still has the original
            // HypotheticalHelperMethod function.

            var instance = new MyClass();

            expect(helperMethod).toHaveBeenCalledWith(1, 2, 3);

        });

    });

});

@keithamus did you find a way to test that your helperMethod is called?