Backstage passes, like aged brie, increases in Quality as its SellIn value approaches

Java/README.md

@@ -15,7 +15,7 @@
 -[x] "Aged Brie" actually increases in Quality the older it gets
 -[x] The Quality of an item is never more than 50
 -[x] "Sulfuras", being a legendary item, never has to be sold or decreases in Quality
--[ ] "Backstage passes", like aged brie, increases in Quality as its SellIn value approaches;
+-[x] "Backstage passes", like aged brie, increases in Quality as its SellIn value approaches;
 -[ ] Quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less but
 -[ ] Quality drops to 0 after the concert
 -[ ] an item can never have its Quality increase above 50, however "Sulfuras" is a legendary item and as such its Quality is 80 and it never alters.

Java/src/test/java/com/gildedrose/GildedRoseTest.java

@@ -91,7 +91,7 @@ public class GildedRoseTest {
     //Sulfuras, Hand of Ragnaros
     @Test
     @DisplayName("\"Sulfuras\", being a legendary item, never has to be sold or decreases in Quality")
-    public void should(){
+    public void shouldNotChangeSulfurasSellInAndQualityValues(){
         Item[] items = new Item[]{TestHelper.getItem("Sulfuras, Hand of Ragnaros", 0, 10)};
         GildedRose app = new GildedRose(items);
 
@@ -106,4 +106,21 @@ public class GildedRoseTest {
         assertEquals(0, app.items[0].sellIn);
     }
 
+    @Test
+    @DisplayName("\"Backstage passes\", like aged brie, increases in Quality as its SellIn value approaches")
+    public void shouldDo(){
+        Item[] items = new Item[]{TestHelper.getItem("Backstage passes to a TAFKAL80ETC concert", 5, 10)};
+        GildedRose app = new GildedRose(items);
+
+        //day 1, increase by 3 the quality
+        app.updateQuality();
+        assertEquals(13, app.items[0].quality);
+        assertEquals(4, app.items[0].sellIn);
+
+        //day 1, increase by 3 the quality
+        app.updateQuality();
+        assertEquals(16, app.items[0].quality);
+        assertEquals(3, app.items[0].sellIn);
+    }
+
 }