ageByOneDay(); $this->assertEquals(19, $item->quality); $this->assertEquals(19, $item->sellIn); } public function testQualityCantBeNegative(): void { $item = new Item('foo', 20, 0); $gildedRoseItem = new DefaultItem($item); $gildedRoseItem->ageByOneDay(); $this->assertEquals(0, $item->quality); } public function testQualityDegradesTwiceAsFastAfterSellBy(): void { $item = new Item('foo', 0, 20); $gildedRoseItem = new DefaultItem($item); $gildedRoseItem->ageByOneDay(); $this->assertEquals(18, $item->quality); } }