Stable product running OK.

php7/src/GildedRose.php

@@ -41,6 +41,16 @@ final class GildedRose
         $this->_items = $items;
     }
 
+    /**
+     * Items getter
+     *
+     * @return array
+     */
+    public function getItems()
+    {
+        return $this->_items;
+    }
+
     /**
      * Advance by a time frame of 1 day
      *

php7/test/GildedRoseTest.php

@@ -22,11 +22,34 @@ namespace App;
  */
 class GildedRoseTest extends \PHPUnit\Framework\TestCase
 {
-    public function testFoo()
+    /**
+     * Product, that is unaffected by processing
+     *
+     * @return void
+     */
+    public function testStableUnaffected()
     {
-        $items      = [new Item("foo", 0, 0)];
+        /**
-        $gildedRose = new GildedRose($items);
+         * Stock items
-        $gildedRose->updateQuality();
+         * 
-        $this->assertEquals("fixme", $items[0]->name);
+         * @var Item[] $items
+         */
+        $items = [
+            new Item('Sulfuras, Hand of Ragnaros', 2, 80),
+            new Item('Sulfuras, Hand of Ragnaros', -1, 80),
+        ];
+
+        $interval = 6;
+        $app = new GildedRose($items);
+
+        for ($i = 0; $i < $interval; $i++) {
+            $app->updateQuality();
+        }
+
+        $this->assertEquals(2, $app->getItems()[0]->sell_in);
+        $this->assertEquals(-1, $app->getItems()[1]->sell_in);
+        $this->assertEquals(80, $app->getItems()[0]->quality);
+        $this->assertEquals(80, $app->getItems()[1]->quality);
     }
+
 }