How to mock $window.location.replace in AngularJS unit test?

Question

I've got the following service:

angular.module("services")
.factory("whatever", function($window) {
  return {
    redirect: function() {
      $window.location.replace("http://www.whatever.com");
    }
  };
});

How to mock $window object in unit test to prevent reloading the page when running tests?

I tried using

spyOn($window.location, 'replace').andReturn(true);

, but it didn't work (still got "Some of your tests did a full page reload!" error) and

$provide.value('$window', {location: {replace: jasmine.createSpy()}})

, but I was getting an error (Error: [ng:areq] Argument 'fn' is not a function, got Object) with stack trace pointing only to angular own source, so it wasn't very helpful...

Answer 1

In Chrome (didn't test inother browsers), location.replace is readonly so spyOn wasn't able to replace it.

$provide.value should work. Something must be wrong somewhere in your code.

Here is a working unit test

describe('whatever', function() {
    var $window, whatever;

    beforeEach(module('services'));

    beforeEach(function() {
      $window = {location: { replace: jasmine.createSpy()} };

      module(function($provide) {
        $provide.value('$window', $window);
      });

      inject(function($injector) {
        whatever = $injector.get('whatever');
      });
    });

    it('replace redirects to http://www.whatever.com', function() {
      whatever.redirect();
      expect($window.location.replace).toHaveBeenCalledWith('http://www.whatever.com');
    });
});

Answer 2

I'm going with an easier but perhaps less elegant solution. I'm writing a wrapper for $window.location, which I can then mock. Relating that to your code, I'd be mocking the whatever.redirect function, rather than mocking $window (I'm assuming here that your real function is more complex).

So I'd end up with:

angular.module("services")
.factory("whatever", function($window) {
  return {
    do_stuff_that_redirects: function() {
      lots of code;
      this.redirect("http://www.whatever.com");
      maybe_more_code_maybe_not;
    },

    redirect: function(url) {
      $window.location.replace(url);
    }
  };
});

I can then directly mock the redirect method, and just trust that since it's only one line of code it can't really go wrong.

spyOn(whatever, 'redirect').andCallFake(function(){});
expect(whatever.redirect).toHaveBeenCalledWith('http:/my.expected/url');

This is sufficient for my purposes, and lets me validate the url called.