/** @test **/ public function it_allows_adding_one_weight_to_another() { $weight_1 = new Weight(500, 'g'); $weight_2 = new Weight(2, 'kg'); $weight_1->add($weight_2); $this->assertEquals(2500, $weight_1->value()); }
/** * Get the total weight for a package of items. * * @param Unit|string $unit The unit the weight should be in * * @return Weight */ public function weight($unit = 'kg') { $total_weight = new Weight(0, $unit); foreach ($this->items as $item) { $total_weight->add($item->weight()); } return $total_weight; }