public function null_carries_no_type_information()
{
$add_five_to_argument = function ($argument, SimpleCalculator $calculator = null) {
if (!$calculator) {
$calculator = new SimpleCalculator();
}
return $calculator->add(5, $argument);
};
assert_that($add_five_to_argument(10))->is_identical_to(__);
assert_that($add_five_to_argument(10), new SimpleCalculator())->is_identical_to(__);
// try removing the "= null" default value assignment and see what happens
assert_that($add_five_to_argument(10), null)->is_identical_to(__);
}
public function objects_can_have_methods()
{
$calculator = new SimpleCalculator();
assert_that($calculator->add(1, 2))->is_identical_to(__);
}