To begin taking advantage of new domain, use wrt default items, and fix business logic

php/src/GildedRose.php

@@ -25,24 +25,8 @@ final class GildedRose
     public function updateQuality(): void
     {
         foreach ($this->items as $item) {
-
-            if ($item->name === 'Sulfuras, Hand of Ragnaros' || $item->name === 'Backstage passes to a TAFKAL80ETC concert' || $item->name === 'Aged Brie') {
             $gildedRoseItem = $this->gildedRoseItemFactory->createGildedRoseItem($item);
             $gildedRoseItem->ageByOneDay();
-                continue;
-            }
-
-            if ($item->quality > 0) {
-                $item->quality = $item->quality - 1;
-            }
-
-            $item->sellIn = $item->sellIn - 1;
-
-            if ($item->sellIn < 0) {
-                if ($item->quality > 0) {
-                    $item->quality = $item->quality - 1;
-                }
-            }
         }
     }
 }

php/src/GildedRoseItem/DefaultItem.php

@@ -14,9 +14,15 @@ class DefaultItem implements GildedRoseItem
     public function ageByOneDay(): void
     {
         $this->item->sellIn -= 1;
-
+        $this->item->quality = max(0, $this->getNewQuality($this->item->quality, $this->item->sellIn));
-        if ($this->item->quality >= 1) {
-            $this->item->quality -= 1;
     }
+
+    private function getNewQuality(int $previousQuality, int $sellIn): int
+    {
+        if ($sellIn < 0) {
+            return $previousQuality - 2;
+        }
+
+        return $previousQuality - 1;
     }
 }

php/tests/behat/feature_files/default-quality-degradation.feature

@@ -16,7 +16,13 @@ Feature: Default quality degradation
     Then the item should have a quality of 15
 
 
-Scenario: Quality cannot be negative
+  Scenario: Quality cannot be negative
       Given an item with a sell-in of 20 and a quality of 0
       When I update the quality
       Then the item should have a quality of 0
+
+
+  Scenario: Once the sell-by date has passed, quality degrades twice as fast
+      Given an item with a sell-in of 0 and a quality of 20
+      When I update the quality
+      Then the item should have a quality of 18

php/tests/phpunit/GildedRoseItem/DefaultItemTest.php

@@ -31,4 +31,13 @@ class DefaultItemTest extends TestCase
 
         $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);
+    }
 }