Unit testing destroy method on directive/service in angular js

Question

I have a few directives and services with registered watchers. I would like to make sure that all watchers are removed when the destroy method is called. Is there anyway of making sure this is the case?

Answer 1

First, I believe you should create a spy on the destroy method, just to make sure it is called.

spyOn(YourService, 'destroy').and.callThrough();
expect(YourService.destroy).toHaveBeenCalled();

So this makes sure your destroy function has been called, now for the watchers part, you can use the code described in this StackOverflow answer (https://stackoverflow.com/a/18526757/2483389) or in this blog entry (https://medium.com/@kentcdodds/counting-angularjs-watchers-11c5134dc2ef).

These provide methods to count the current number of watchers you are using. You should expect it to be 0 after the destroy method was called.