Tests improved before another major refactory

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

@@ -3,8 +3,8 @@ package com.gildedrose;
 public class AgedBrieUpdater extends ItemUpdater {
     @Override
     void updateQuality(Item item) {
-        if (item.quality < 50) {
+        if (canUpdateQuality(item)) {
-            item.quality += 1;
+            item.quality += getDegradeValue(item);
         }
     }
 
@@ -12,4 +12,14 @@ public class AgedBrieUpdater extends ItemUpdater {
     void updateSellIn(Item item) {
         item.sellIn -= 1;
     }
+
+    @Override
+    boolean canUpdateQuality(Item item) {
+        return item.quality < HIGHEST_QUALITY;
+    }
+
+    @Override
+    int getDegradeValue(Item item) {
+        return INCREASE_NORMAL;
+    }
 }

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

@@ -3,18 +3,10 @@ package com.gildedrose;
 public class BackstagePassUpdater extends ItemUpdater {
     @Override
     void updateQuality(Item item) {
-        if (item.sellIn < 0) {
+        if (sellByDateLessThan(item, 0)) {
             item.quality = 0;
-        } else if (item.quality < 50) {
+        } else if (canUpdateQuality(item)) {
-            item.quality += 1;
+            item.quality += getDegradeValue(item);
-
-            if (item.sellIn < 11 && item.quality < 50) {
-                item.quality += 1;
-            }
-
-            if (item.sellIn < 6 && item.quality < 50) {
-                item.quality += 1;
-            }
         }
     }
 
@@ -22,4 +14,23 @@ public class BackstagePassUpdater extends ItemUpdater {
     void updateSellIn(Item item) {
         item.sellIn -=1;
     }
+
+    @Override
+    boolean canUpdateQuality(final Item item) {
+        return item.quality < HIGHEST_QUALITY;
+    }
+
+    @Override
+    int getDegradeValue(final Item item) {
+        if (sellByDateLessThan(item, 6)) {
+            return INCREASE_THRICE_AS_FAST;
+        } else if (sellByDateLessThan(item, 11) ) {
+            return INCREASE_TWICE_AS_FAST;
+        }
+        return INCREASE_NORMAL;
+    }
+
+    private static boolean sellByDateLessThan(final Item item, final int remainingDayCount) {
+        return item.sellIn < remainingDayCount;
+    }
 }

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

@@ -3,10 +3,8 @@ package com.gildedrose;
 public class ConjuredUpdater extends ItemUpdater {
     @Override
     void updateQuality(Item item) {
-        if (item.quality > 0) {
+        if (canUpdateQuality(item)) {
-            item.quality -= 2;
+            item.quality += getDegradeValue(item);
-            if (item.quality < 0 )
-                item.quality =0;
         }
     }
 
@@ -14,4 +12,16 @@ public class ConjuredUpdater extends ItemUpdater {
     void updateSellIn(Item item) {
         item.sellIn -= 1;
     }
+
+    @Override
+    boolean canUpdateQuality(Item item) {
+        return item.quality < HIGHEST_QUALITY && item.quality > 0;
+    }
+
+    @Override
+    int getDegradeValue(Item item) {
+        return item.quality + DEGRADE_TWICE_AS_FAST < 0 ?
+                DEGRADE_NORMAL :
+                DEGRADE_TWICE_AS_FAST;
+    }
 }

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

@@ -8,55 +8,9 @@ class GildedRose {
     }
 
     public void updateQuality() {
-        for (int i = 0; i < items.length; i++) {
+        for (Item item : items) {
-            if (!items[i].name.equals("Aged Brie")
+            ItemUpdaterFactory.getItemUpdater(item)
-                    && !items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                    .updateStateFor(item);
-                if (items[i].quality > 0) {
-                    if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                        items[i].quality = items[i].quality - 1;
-                    }
-                }
-            } else {
-                if (items[i].quality < 50) {
-                    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) {
-                            if (items[i].quality < 50) {
-                                items[i].quality = items[i].quality + 1;
-                            }
-                        }
-                    }
-                }
-            }
-
-            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                items[i].sellIn = items[i].sellIn - 1;
-            }
-
-            if (items[i].sellIn < 0) {
-                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;
-                    }
-                } else {
-                    if (items[i].quality < 50) {
-                        items[i].quality = items[i].quality + 1;
-                    }
-                }
-            }
         }
     }
 }

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

@@ -0,0 +1,62 @@
+package com.gildedrose;
+
+class GildedRoseOld {
+    Item[] items;
+
+    public GildedRoseOld(Item[] items) {
+        this.items = items;
+    }
+
+    public void updateQuality() {
+        for (int i = 0; i < items.length; i++) {
+            if (!items[i].name.equals("Aged Brie")
+                    && !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 {
+                if (items[i].quality < 50) {
+                    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) {
+                            if (items[i].quality < 50) {
+                                items[i].quality = items[i].quality + 1;
+                            }
+                        }
+                    }
+                }
+            }
+
+            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
+                items[i].sellIn = items[i].sellIn - 1;
+            }
+
+            if (items[i].sellIn < 0) {
+                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;
+                    }
+                } else {
+                    if (items[i].quality < 50) {
+                        items[i].quality = items[i].quality + 1;
+                    }
+                }
+            }
+        }
+    }
+}

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

@@ -1,16 +0,0 @@
-package com.gildedrose;
-
-class GildedRosePrototype {
-    Item[] items;
-
-    public GildedRosePrototype(Item[] items) {
-        this.items = items;
-    }
-
-    public void updateQuality() {
-        for (Item item : items) {
-            ItemUpdaterFactory.getItemUpdater(item)
-                    .updateStateFor(item);
-        }
-    }
-}

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

@@ -1,10 +1,23 @@
 package com.gildedrose;
 
 public abstract class ItemUpdater {
+    static int HIGHEST_QUALITY = 50;
+    static int DEGRADE_NORMAL = -1;
+    static int DEGRADE_TWICE_AS_FAST = -2;
+    static int INCREASE_NORMAL = 1;
+    static int INCREASE_TWICE_AS_FAST = 2;
+    static int INCREASE_THRICE_AS_FAST = 3;
+
     public void updateStateFor(Item item){
         updateSellIn(item);
         updateQuality(item);
     }
     abstract void updateQuality(Item item);
     abstract void updateSellIn(Item item);
+    abstract boolean canUpdateQuality(Item item);
+    abstract int getDegradeValue(Item item);
+
+    public int getHighestQuality() {
+        return HIGHEST_QUALITY;
+    }
 }

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

@@ -11,7 +11,7 @@ public class ItemUpdaterFactory {
         registeredCustomUpdaters.put("Aged Brie", new AgedBrieUpdater());
         registeredCustomUpdaters.put("Backstage passes to a TAFKAL80ETC concert", new BackstagePassUpdater());
         registeredCustomUpdaters.put("Sulfuras, Hand of Ragnaros", new SulfurasUpdater());
-        registeredCustomUpdaters.put("Conjured", new ConjuredUpdater());
+        registeredCustomUpdaters.put("Conjured Mana Cake", new ConjuredUpdater());
     }
 
     public static void registerCustomUpdater(String type, ItemUpdater updater ){
@@ -22,17 +22,4 @@ public class ItemUpdaterFactory {
         return Optional.ofNullable(registeredCustomUpdaters.get(item.name))
                 .orElse(new StandardItemUpdater());
     }
-
-    /*public static ItemUpdater getItemUpdater_(Item item) {
-        if ("Aged Brie".equals(item.name))
-            return new AgedBrieUpdater();
-        else if ("Backstage passes to a TAFKAL80ETC concert".equals(item.name))
-            return new BackstagePassUpdater();
-        else if ("Sulfuras, Hand of Ragnaros".equals(item.name))
-            return new SulfurasUpdater();
-        else if ("Conjured".equals(item.name))
-            return new ConjuredUpdater();
-        else
-            return new StandardItemUpdater();
-    }*/
 }

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

@@ -4,8 +4,8 @@ public class StandardItemUpdater extends ItemUpdater{
 
     @Override
     void updateQuality(Item item) {
-        if (item.quality > 0) {
+        if (canUpdateQuality(item)) {
-            item.quality  -= 1;
+            item.quality += getDegradeValue(item);
         }
     }
 
@@ -13,4 +13,18 @@ public class StandardItemUpdater extends ItemUpdater{
     void updateSellIn(Item item) {
         item.sellIn -= 1;
     }
+
+    @Override
+    boolean canUpdateQuality(Item item) {
+        return item.quality < HIGHEST_QUALITY && item.quality > 0;
+    }
+
+    @Override
+    int getDegradeValue(Item item) {
+        if (item.sellIn < 0) {
+            return item.quality + DEGRADE_TWICE_AS_FAST < 0 ? DEGRADE_NORMAL : DEGRADE_TWICE_AS_FAST;
+        } else {
+            return DEGRADE_NORMAL;
+        }
+    }
 }

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

@@ -1,13 +1,32 @@
 package com.gildedrose;
 
 public class SulfurasUpdater extends ItemUpdater {
+
     @Override
     void updateQuality(Item item) {
         System.out.println("########Sulfuras is a legendary product");
+        // TODO
+        item.quality = 80;
     }
 
     @Override
     void updateSellIn(Item item) {
         System.out.println("########Never gets old");
     }
+
+    @Override
+    boolean canUpdateQuality(Item item) {
+        // "Sulfuras", being a legendary item, never decreases in Quality
+        return false;
+    }
+
+    @Override
+    int getDegradeValue(Item item) {
+        // "Sulfuras", being a legendary item, never has to be sold
+        return 0;
+    }
+
+    public int getHighestQuality() {
+        return 80;
+    }
 }

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

@@ -4,14 +4,131 @@ import static org.junit.Assert.*;
 
 import org.junit.Test;
 
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
 public class GildedRoseTest {
 
+    /*
+     First an introduction to our system:
+
+	- All items have a SellIn value which denotes the number of days we have to sell the item
+	- All items have a Quality value which denotes how valuable the item is
+	- At the end of each day our system lowers both values for every item
+
+Pretty simple, right? Well this is where it gets interesting:
+
+	- Once the sell by date has passed, Quality degrades twice as fast
+	- The Quality of an item is never negative
+	- "Aged Brie" actually increases in Quality the older it gets
+	- The Quality of an item is never more than 50
+	- "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;
+	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
+
+    We have recently signed a supplier of conjured items. This requires an update to our system:
+
+        - "Conjured" items degrade in Quality twice as fast as normal items
+
+    Feel free to make any changes to the UpdateQuality method and add any new code as long as everything
+    still works correctly. However, do not alter the Item class or Items property as those belong to the
+    goblin in the corner who will insta-rage and one-shot you as he doesn't believe in shared code
+    ownership (you can make the UpdateQuality method and Items property static if you like, we'll cover
+    for you).
+
+    Just for clarification, 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.
+
+     */
+    private final Item sulfuras = new Item("Sulfuras, Hand of Ragnaros", 0, 80);
+
+    private final Item standardWithHighestQuality = new Item("Standard", 5, 50);
+    private final Item agedBrieWithHighestQuality = new Item("Aged Brie", 5, 50);
+    private final Item conjuredWithHighestQuality = new Item("Conjured Mana Cake", 5, 50);
+    private final Item backstageWithHighestQuality = new Item("Backstage passes to a TAFKAL80ETC concert", 5, 50);
+
+    private final Item standardWithLowQuality = new Item("Standard", 0, 1);
+    private final Item agedBrieWithLowQuality = new Item("Aged Brie", 0, 1);
+    private final Item conjuredWithLowQuality = new Item("Conjured Mana Cake", 0, 1);
+    private final Item backstageWithLowQuality = new Item("Backstage passes to a TAFKAL80ETC concert", 0, 1);
+
     @Test
-    public void foo() {
+    public void standardItem_shouldDegradeNormal_whenSellByDateNotPassed() {
-        Item[] items = new Item[] { new Item("foo", 0, 0) };
+        final int originalQuality = 40;
-        GildedRose app = new GildedRose(items);
+        final Item[] items = new Item[] { new Item("Standard", 4, originalQuality) };
+        final GildedRose app = new GildedRose(items);
         app.updateQuality();
-        assertEquals("fixme", app.items[0].name);
+        assertEquals("Standard", app.items[0].name);
+        assertEquals(3, app.items[0].sellIn);
+        assertEquals(originalQuality - 1, app.items[0].quality);
+    }
+
+    @Test
+    public void standardItem_shouldDegradeTwiceAsFast_whenSellByDatePassed() {
+        final int originalQuality = 40;
+        final Item[] items = new Item[] { new Item("Standard", 0, originalQuality) };
+        final GildedRose app = new GildedRose(items);
+        app.updateQuality();
+        assertEquals("Standard", app.items[0].name);
+        assertEquals(-1, app.items[0].sellIn);
+        assertEquals(originalQuality - 2, app.items[0].quality);
+
+        app.updateQuality();
+        assertEquals(-2, app.items[0].sellIn);
+        assertEquals(originalQuality - 4, app.items[0].quality);
+    }
+
+
+    @Test
+    public void sulfurus_shouldNeverDegradeAndBeSold() {
+        final Item[] items = new Item[] { sulfuras};
+        final GildedRose app = new GildedRose(items);
+        app.updateQuality();
+        assertEquals("Sulfuras, Hand of Ragnaros", app.items[0].name);
+        assertEquals(0, app.items[0].sellIn);
+        assertEquals(80, app.items[0].quality);
+    }
+
+    @Test
+    public void qualityOfItem_exceptLegendaryItems_cantBeMoreThan_50() {
+        final Item[] items = new Item[] {standardWithHighestQuality, backstageWithHighestQuality,
+                agedBrieWithHighestQuality, conjuredWithHighestQuality};
+        final GildedRose app = new GildedRose(items);
+        app.updateQuality();
+        final Optional<Item> qualityHigherThan80 = Arrays.stream(app.items).filter(item -> item.quality > 50).findAny();
+
+        assertFalse(qualityHigherThan80.isPresent());
+    }
+
+    @Test
+    public void qualityOfItem_onlyLegendaryItems_cantBeMoreThan_50() {
+        final Item[] items = new Item[] { sulfuras, standardWithHighestQuality, backstageWithHighestQuality,
+                agedBrieWithHighestQuality, conjuredWithHighestQuality};
+        final GildedRose app = new GildedRose(items);
+        app.updateQuality();
+        final List<Item> qualityHigherThan80List = Arrays.stream(app.items).filter(item -> item.quality > 50).collect(Collectors.toList());
+
+        assertEquals(1, qualityHigherThan80List.size());
+        assertEquals(sulfuras.name, qualityHigherThan80List.get(0).name);
+    }
+
+    @Test
+    public void qualityOfItem_canNeverBeNegative() {
+        final Item[] items = new Item[] {sulfuras, standardWithLowQuality, backstageWithLowQuality,
+                agedBrieWithLowQuality, conjuredWithLowQuality};
+        final GildedRose app = new GildedRose(items);
+        app.updateQuality();
+        final Optional<Item> qualityNegative = Arrays.stream(app.items).filter(item -> item.quality < 0 ).findAny();
+
+        assertFalse(qualityNegative.isPresent());
+
+        app.updateQuality();
+        final Optional<Item> qualityNegativeAfter2ndUpdate = Arrays.stream(app.items).filter(item -> item.quality < 0 ).findAny();
+
+        assertFalse(qualityNegativeAfter2ndUpdate.isPresent());
     }
 
 }