JavaScripot Spy Class for 3rd party testing frameworks

Simple Spy class

(function () {


    window.EhSpy = function (suspect, methodName) {

        var self = this;

        self.original = suspect[methodName];

        suspect[methodName] = function () {
            self.wasCalled = true;
            self.reset();
        };

        self.reset = function () {
            suspect[methodName] = self.original;
        };

        self.hasBeenCalled = function () {
            return self.wasCalled;
        }

    };


}())


(function () {

    describe("SpyClass", function () {


        it("Should overwrite the original object function", function () {

            var suspect = {
                func: function () {
                    return "hello world";
                }
            };

            var original = suspect.func;

            var mySpy = new EhSpy(suspect, "func");

            expect(original.toString()).not.toEqual(suspect.func.toString());
        });


        it("Should reset the original value of calling reset", function () {
            var suspect = {
                func: function () {
                    return "hello world";
                }
            };

            var original = suspect.func;

            var mySpy = new EhSpy(suspect, "func");

            mySpy.reset();

            expect(original.toString()).toEqual(suspect.func.toString());

        });


        it("Should reset the function value after it has been spied on", function() {

            var suspect = {
                func: function () {
                    return "hello world";
                }
            };

            var original = suspect.func;

            var mySpy = new EhSpy(suspect, "func");

            suspect.func();

            expect(original.toString()).toEqual(suspect.func.toString());
        });


        it("Should return wasCalled when hasBeenCalled is invoked", function () {

            var suspect = {
                func: function () {
                    return "hello world";
                }
            };

            var original = suspect.func;

            var mySpy = new EhSpy(suspect, "func");

            suspect.func();

            expect(mySpy.hasBeenCalled()).toEqual(true);
        });


    });

}());