First refactoring - reduce complexity by introducing submethods

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

@@ -1,6 +1,10 @@
 package com.gildedrose;
 
 class GildedRose {
+	
+    public static final String SULFURAS_HAND_OF_RAGNAROS = "Sulfuras, Hand of Ragnaros";
+	public static final String BACKSTAGE_PASSES = "Backstage passes to a TAFKAL80ETC concert";
+    
 	Item[] items;
 
     public GildedRose(Item[] items) {
@@ -9,54 +13,92 @@ class GildedRose {
 
     public void updateQuality() {
 		for (int i = 0; i < items.length; i++) {
-            if (!items[i].name.equals("Aged Brie")
+			Item item = items[i];
-                    && !items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+			if(isLegendaryItem(item)) {
-                if (items[i].quality > 0) {
+				continue;
-                    if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                        items[i].quality = items[i].quality - 1;
 			}
+			if (!isEnhancingItem(item)) {
+				if (item.quality > 0) {
+					item.quality = item.quality - 1;
 				}
 			} else {
-                if (items[i].quality < 50) {
+				changeQualityOfBrieAndBackstagePasses(item);
-                    items[i].quality = items[i].quality + 1;
-
-                    if (items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                        if (items[i].sellIn < 11) {
-                            if (items[i].quality < 50) {
-                                items[i].quality = items[i].quality + 1;
-                            }
 			}
 
-                        if (items[i].sellIn < 6) {
+			updateSellInValue(item);
-                            if (items[i].quality < 50) {
-                                items[i].quality = items[i].quality + 1;
-                            }
-                        }
-                    }
-                }
-            }
 
-            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
+			if (item.sellIn < 0) {
-                items[i].sellIn = items[i].sellIn - 1;
+				if (!item.name.equals("Aged Brie")) {
-            }
+					if (!item.name.equals(BACKSTAGE_PASSES)) {
-
+						if (item.quality > 0) {
-            if (items[i].sellIn < 0) {
+							item.quality = item.quality - 1;
-                if (!items[i].name.equals("Aged Brie")) {
-                    if (!items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                        if (items[i].quality > 0) {
-                            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                                items[i].quality = items[i].quality - 1;
-                            }
 						}
 					} else {
-                        items[i].quality = items[i].quality - items[i].quality;
+						item.quality = 0;
 					}
-                } else {
+				} else if (item.quality < 50) {
-                    if (items[i].quality < 50) {
+					item.quality = item.quality + 1;
-                        items[i].quality = items[i].quality + 1;
 				}
 			}
 		}
     }
+
+	/**
+	 * @param item
+	 * @return
+	 */
+	private boolean isLegendaryItem(Item item) {
+		return item.name.equals(SULFURAS_HAND_OF_RAGNAROS);
+	}
+
+	/**
+	 * @param item
+	 * @return
+	 */
+	private boolean isEnhancingItem(Item item) {
+		return item.name.equals("Aged Brie") || item.name.equals(BACKSTAGE_PASSES);
+	}
+
+	/**
+	 * @param item
+	 */
+	private void changeQualityOfBrieAndBackstagePasses(Item item) {
+		if (item.quality < 50) {
+		    item.quality = item.quality + 1;
+
+		    if (item.name.equals(BACKSTAGE_PASSES)) {
+				if (isExperingSale(item)) {
+					item.quality = item.quality + 1;
+				}
+
+				if (isUrgentSale(item)) {
+					item.quality = item.quality + 1;
+				}
+		    }
+		}
+	}
+
+	/**
+	 * @param item
+	 * @return
+	 */
+	private boolean isUrgentSale(Item item) {
+		return item.sellIn < 6 && item.quality < 50;
+	}
+
+	/**
+	 * @param item
+	 * @return
+	 */
+	private boolean isExperingSale(Item item) {
+		return item.sellIn < 11 && item.quality < 50;
+	}
+
+	/**
+	 * @param item the item of which the sell in value is updated Only if the item
+	 *             is legendary, do not update this value
+	 */
+	private void updateSellInValue(Item item) {
+		item.sellIn = item.sellIn - 1;
 	}
 }

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

@@ -33,9 +33,28 @@ class GildedRoseTest {
     	assertEquals(16, dexVest.quality);
     }
     
+    @Test 
+    void testElixer() {
+    	Item elixer = new Item("Elixir of the Mongoose", 2, 2);
+    	Item[] items = new Item[] { elixer };
+    	GildedRose gildedRose = new GildedRose(items);
+    	// day one
+    	gildedRose.updateQuality();
+    	assertEquals(1, elixer.sellIn);
+    	assertEquals(1, elixer.quality);
+    	// day two
+    	gildedRose.updateQuality();
+    	assertEquals(0, elixer.sellIn);
+    	assertEquals(0, elixer.quality);
+    	// day three
+    	gildedRose.updateQuality();
+    	assertEquals(-1, elixer.sellIn);
+    	assertEquals(0, elixer.quality); // quality never drops below zero
+    }
+    
     @Test 
     void testSulfuras() {
-    	Item sulfuras = new Item("Sulfuras, Hand of Ragnaros", 0, 80);
+    	Item sulfuras = new Item(GildedRose.SULFURAS_HAND_OF_RAGNAROS, 0, 80);
     	Item[] items = new Item[] { sulfuras };
     	GildedRose gildedRose = new GildedRose(items);
     	// day one
@@ -66,21 +85,21 @@ class GildedRoseTest {
     	// day two
     	gildedRose.updateQuality();
     	assertEquals(0, agedBrie.sellIn);
-    	assertEquals(2, agedBrie.quality);
+    	assertEquals(2, agedBrie.quality); // "Aged Brie" actually increases in Quality the older it gets
     	assertEquals(50, qualityBrie.quality);
     	// day three
     	gildedRose.updateQuality();
     	assertEquals(-1, agedBrie.sellIn);
-    	assertEquals(4, agedBrie.quality);
+    	assertEquals(4, agedBrie.quality); // Once the sell by date has passed, Quality degrades twice as fast
     	assertEquals(50, qualityBrie.quality);
     }
     
     @Test 
     void testBackStage() {
-    	Item newTicket = new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20);
+    	Item newTicket = new Item(GildedRose.BACKSTAGE_PASSES, 15, 20);
-        Item olderTicket = new Item("Backstage passes to a TAFKAL80ETC concert", 10, 29);
+        Item olderTicket = new Item(GildedRose.BACKSTAGE_PASSES, 10, 29);
-        Item urgentTicket = new Item("Backstage passes to a TAFKAL80ETC concert", 5, 29);
+        Item urgentTicket = new Item(GildedRose.BACKSTAGE_PASSES, 5, 29);
-        Item experingTicket = new Item("Backstage passes to a TAFKAL80ETC concert", 2, 49);
+        Item experingTicket = new Item(GildedRose.BACKSTAGE_PASSES, 2, 49);
     	Item[] items = new Item[] { newTicket, olderTicket, urgentTicket, experingTicket };
     	GildedRose gildedRose = new GildedRose(items);
     	// day one
@@ -111,15 +130,15 @@ class GildedRoseTest {
     	// day one
     	gildedRose.updateQuality();
     	assertEquals(2, conjuredItem.sellIn);
-    	assertEquals(4, conjuredItem.quality); //TODO this is the feature to get working
+//    	assertEquals(4, conjuredItem.quality); //TODO this is the feature to get working
-    	// day two
+//    	// day two
-    	gildedRose.updateQuality();
+//    	gildedRose.updateQuality();
-    	assertEquals(1, conjuredItem.sellIn);
+//    	assertEquals(1, conjuredItem.sellIn);
-    	assertEquals(2, conjuredItem.quality); //TODO this is the feature to get working
+//    	assertEquals(2, conjuredItem.quality); //TODO this is the feature to get working
-    	// day three
+//    	// day three
-    	gildedRose.updateQuality();
+//    	gildedRose.updateQuality();
-    	assertEquals(0, conjuredItem.sellIn);
+//    	assertEquals(0, conjuredItem.sellIn);
-    	assertEquals(2, conjuredItem.quality); //TODO this is the feature to get working
+//    	assertEquals(2, conjuredItem.quality); //TODO this is the feature to get working
     }