In case of should not remove user, we're going to do some similar stuff, we're just going to tweak userId. I can actually copy the contents of our first test case, paste it into the second one, and all we need to do is make a few tweaks. I'm going to change the ID to an invalid ID like 99. We are still going to call removeUser with the ID. In this case, though instead of expecting user to have an id property, we're going to expect that user does not exist using toNotExist. Next up, we're going to expect the length has not changed, and we're going to make sure that the length still equals 3:
it ('should not remove user', () => { var userId = '99'; var user = users.removeUser(userId); expect(user).toBe(userId); ...
