dnspec.php

<?php

namespace Dn;

class StringCalculatorSpec
{
    public function specification()
    {
        return [
            'it_is_initializable' => function ($it) {
                $it->shouldHaveType('StringCalculator');
            },
            'it_requires_string_input' => function ($it) {
                $it->shouldThrow('\InvalidArgumentException')->during('add', [null]);
            },
            'it_adds_2_numbers_separated_by_comma' => function ($it) {
                $it->add('1,2')->shouldReturn(3);
            }
        ];
    }
}