Jasmine SpyOn same method more than once

Question

I have an angular controller with a method that calls $location.search() twice.

First time is just $location.search() to return the value.
Second time is $location.search("foo", null) to clear it.

I have the following spy in my unit test:
spyOn($location, "search").and.returnValue({ foo: "bar" });

It appears the spy returns {foo:"bar"} even when my implementation does $location.search("foo", null).

I need a way to have two different spies for the same method depending on the arguments.

I need this expect:
expect($location.search().foo).toEqual(null);
to pass at the end of the unit test.

Answer 1

You can go about it different ways. If you have time to change the spy implementation during your testcase, you can do this:

var searchSpy = spyOn($location,'search');

searchSpy.and.returnValue(null);
// do stuff
searchSpy.and.returnValue({ foo: "bar" });
// do other stuff

If the calls are triggered by a method in your code, and you cannot change the spy implementation in between, then you can create a function that takes the arguments and responds appropriately:

spyOn($location,'search').and.callFake(function(someParam){
  if (someParam) { 
      return { foo: "bar" };
  } else {
      return { foo: null };
  }
});

Of course you can go crazy with logic in your callFake implementation, but beware, I think in that case it might be a code smell. Anyway, happy coding!

Answer 2

Also it's possible to call spy properties on the mocked object directly. The code may look like:

spyOn($location,'search');

$location.search.and.returnValue(null);
// do stuff
$location.search.and.returnValue({ foo: "bar" })
// do other stuff

In case of typescript it may look like:

spyOn($location,'search');

(<jasmine.Spy>$location.search).and.returnValue(null);
// do stuff
(<jasmine.Spy>$location.search).and.returnValue({ foo: "bar" })
// do other stuff

Posting this answer because it may look a bit cleaner and doesn't require additional variables.