angular tests reset object foreach test code example
Example: angular9 spy
it("should be able to upper case a string", function () {
var spytoUpperCase = spyOn(String.prototype, 'toUpperCase')
expect(utils.toUpperCase).toBeDefined();
expect(utils.toUpperCase("hello world")).toEqual("HELLO WORLD");
expect(String.prototype.toUpperCase).toHaveBeenCalled();
expect(spytoUpperCase.calls.count()).toEqual(1);
});