Refactor backstage pass quality and sellIn update logic

Author: aaccioly

Java/src/main/java/com/gildedrose/GildedRose.java

@@ -43,41 +43,25 @@ private void updateItem(Item item) {
                 item.quality += qualityDelta;
             }
             return;
-        }
-
-        if (!isBackStagePass(item.name)) {
-            if (item.quality > 0) {
-                item.quality = item.quality - 1;
-            }
-        } else {
-            if (item.quality < 50) {
-                item.quality = item.quality + 1;
-
-                if (item.sellIn < 11) {
-                    if (item.quality < 50) {
-                        item.quality = item.quality + 1;
-                    }
-                    if (item.sellIn < 6) {
-                        if (item.quality < 50) {
-                            item.quality = item.quality + 1;
-                        }
-                    }
+        } else if (isBackStagePass(item.name)) {
+            item.sellIn--;
+            if (item.sellIn < 0) {
+                item.quality = 0;
+            } else {
+                if (item.quality < 50) {
+                    var qualityDelta = item.sellIn < 5 ? 3 : item.sellIn < 10 ? 2 : 1;
+                    item.quality += qualityDelta;
                 }
             }
+            return;
         }
 
         // all items except Sulfuras -> decrease sellIn
         item.sellIn = item.sellIn - 1;
 
-        if (item.sellIn < 0) {
-            // normal items -> quality decreases twice as fast after expiration date
-            if (!isBackStagePass(item.name)) {
-                if (item.quality > 0) {
-                    item.quality = item.quality - 1;
-                }
-            } else {
-                item.quality = 0;
-            }
+        if (item.quality > 0) {
+            var qualityDelta = item.sellIn < 0 ? 2 : 1;
+            item.quality = item.quality - qualityDelta;
         }
     }
 }

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

@@ -101,6 +101,32 @@ class BackstagePass {
         void isBackstagePass() {
             assertThat(GildedRose.isBackStagePass(backStagePass.name)).isTrue();
         }
+
+        @DisplayName("quality increases by 1 when sellIn is greater than 10")
+        @Test
+        void qualityIncreasesBy1WhenSellInIsGreaterThan10() {
+            GildedRose app = createGildedRose(backStagePass);
+            app.updateQuality();
+            assertThat(backStagePass.quality).isEqualTo(11);
+        }
+
+        @DisplayName("quality increases by 2 when sellIn is between 10 and 6")
+        @Test
+        void qualityIncreasesBy2WhenSellInIsBetween10And6() {
+            backStagePass.sellIn = 10;
+            GildedRose app = createGildedRose(backStagePass);
+            app.updateQuality();
+            assertThat(backStagePass.quality).isEqualTo(12);
+        }
+
+        @DisplayName("quality increases by 3 when sellIn is between 5 and 0")
+        @Test
+        void qualityIncreasesBy3WhenSellInIsBetween5And0() {
+            backStagePass.sellIn = 5;
+            GildedRose app = createGildedRose(backStagePass);
+            app.updateQuality();
+            assertThat(backStagePass.quality).isEqualTo(13);
+        }
     }
 
     public GildedRose createGildedRose(Item item) {