Jasmine: how to spy on inner object method call?

bdd, jasmine, javascript, testing, unit-testing

Solution

You have yo spy on the prototype of `Child` object.

describe("Person", function () {
  it("calls the getAge() function", function () {
    var spy = spyOn(Child.prototype, "getAge");
    var fakePerson = new Person();
    fakePerson.pingChild();
    expect(spy).toHaveBeenCalled();
  });
});

Problem

I have two prototypes I want to test: ``` var Person = function() {}; Person.prototype.pingChild = function(){ var boy = new Child(); boy.getAge(); } var Child = function() {}; Child.prototype.getAge = function() { return 42; }; ``` What exactly I want to test: to check that `getAge()` method is called inside of the `pingChild()` method That is Jasmine specs I try to use for this purpose: ``` describe("Person", function() { it("calls the getAge() function", function() { var fakePerson = new Person(); var chi = new Child(); spyOn(fakePerson, "getAge"); fakePerson.pingChild(); expect(chi.getAge).toHaveBeenCalled(); }); }); describe("Person", function() { it("calls the getAge() function", function() { var fakePerson = new Person(); spyOn(fakePerson, "getAge"); fakePerson.pingChild(); expect(fakePerson.getAge).toHaveBeenCalled(); }); }); describe("Person", function() { it("calls the getAge() function", function() { var fakePerson = new Person(); var chi = new Child(); spyOn(chi, "getAge"); fakePerson.pingChild(); expect(chi.getAge).toHaveBeenCalled(); }); }); ``` but all of them shows just errors: - getAge() method does not exist - getAge() method does not exist - Expected spy getAge to have been called So, is there any way to test such cases using Jasmine, and if yes - how can it be done?

Original source