how-would-you-test.php

<?php

class User extends Eloquent {
    public function getOldest()
    {
        return $this->orderBy('age', 'desc')->first();
    }
}

2

2 because we're dealing with datas from the database. Otherwise 3 if you intend to test a method that format a given data.

2 and 3

2

2, using an in-memory database. Good tutorial here: http://code.tutsplus.com/tutorials/testing-like-a-boss-in-laravel-models--net-30087