Refactor and add more tests

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

@@ -7,30 +7,30 @@ public class GildedRose {
     public static void updateQuality(Item[] items) {
         for (Item item : items) {
             if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-                item.sellIn--;
+                item.sellIn--; // Decrease sellIn for all items except Sulfuras
 
                 if (item.name.equals("Aged Brie")) {
                     increaseQuality(item);
                     if (item.sellIn < 0) {
-                        increaseQuality(item);
+                        increaseQuality(item); // Quality increases twice after sellIn passes
                     }
                 } else if (item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
                     increaseQuality(item);
                     if (item.sellIn < 11) {
-                        increaseQuality(item);
+                        increaseQuality(item); // Quality increases by 2 when sellIn is 10 or less
                     }
                     if (item.sellIn < 6) {
-                        increaseQuality(item);
+                        increaseQuality(item); // Quality increases by 3 when sellIn is 5 or less
                     }
                     if (item.sellIn < 0) {
-                        item.quality = MIN_QUALITY;
+                        item.quality = MIN_QUALITY; // Quality drops to 0 after the concert
                     }
                 } else if (item.name.equals("Conjured Mana Cake")) {
-                    decreaseQuality(item, 2);
+                    decreaseQuality(item, 2); // Quality decreases twice as fast for conjured items
                 } else {
-                    decreaseQuality(item);
+                    decreaseQuality(item); // Normal items decrease in quality
                     if (item.sellIn < 0) {
-                        decreaseQuality(item);
+                        decreaseQuality(item); // Quality decreases twice after sellIn passes
                     }
                 }
             }

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

@@ -1,17 +1,93 @@
 package com.gildedrose;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-class GildedRoseTest {
+public class GildedRoseTest {
 
-    @Test
-    void foo() {
-        Item[] items = new Item[] { new Item("foo", 0, 0) };
-        GildedRose app = new GildedRose();
-        app.updateQuality(items);
-        assertEquals("fixme", items[0].name);
+    private Item[] items;
+
+    @BeforeEach
+    public void setUp() {
+        items = new Item[]{
+            new Item("+5 Dexterity Vest", 10, 20),
+            new Item("Aged Brie", 2, 0),
+            new Item("Elixir of the Mongoose", 5, 7),
+            new Item("Sulfuras, Hand of Ragnaros", 0, 80),
+            new Item("Sulfuras, Hand of Ragnaros", -1, 80),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 10, 49),
+            new Item("Backstage passes to a TAFKAL80ETC concert", 5, 49),
+            new Item("Conjured Mana Cake", 3, 6)
+        };
     }
 
+    @Test
+    public void testDay1() {
+        GildedRose.updateQuality(items);
+
+        // Assertions for Day 1
+        assertEquals(9, items[0].sellIn);
+        assertEquals(19, items[0].quality);
+
+        assertEquals(1, items[1].sellIn);
+        assertEquals(1, items[1].quality);
+
+        assertEquals(4, items[2].sellIn);
+        assertEquals(6, items[2].quality);
+
+        assertEquals(0, items[3].sellIn);
+        assertEquals(80, items[3].quality);
+
+        assertEquals(-1, items[4].sellIn);
+        assertEquals(80, items[4].quality);
+
+        assertEquals(14, items[5].sellIn);
+        assertEquals(21, items[5].quality);
+
+        assertEquals(9, items[6].sellIn);
+        assertEquals(50, items[6].quality);
+
+        assertEquals(4, items[7].sellIn);
+        assertEquals(50, items[7].quality);
+
+        assertEquals(2, items[8].sellIn);
+        assertEquals(4, items[8].quality);
+    }
+
+    @Test
+    public void testDay2() {
+        GildedRose.updateQuality(items);
+        GildedRose.updateQuality(items);
+
+        // Assertions for Day 2
+        assertEquals(8, items[0].sellIn);
+        assertEquals(18, items[0].quality);
+
+        assertEquals(0, items[1].sellIn);
+        assertEquals(2, items[1].quality);
+
+        assertEquals(3, items[2].sellIn);
+        assertEquals(5, items[2].quality);
+
+        assertEquals(0, items[3].sellIn);
+        assertEquals(80, items[3].quality);
+
+        assertEquals(-1, items[4].sellIn);
+        assertEquals(80, items[4].quality);
+
+        assertEquals(13, items[5].sellIn);
+        assertEquals(22, items[5].quality);
+
+        assertEquals(8, items[6].sellIn);
+        assertEquals(50, items[6].quality);
+
+        assertEquals(3, items[7].sellIn);
+        assertEquals(50, items[7].quality);
+
+        assertEquals(1, items[8].sellIn);
+        assertEquals(2, items[8].quality);
+    }
 }

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

@@ -1,37 +0,0 @@
-package com.gildedrose;
-
-public class TexttestFixture {
-    public static void main(String[] args) {
-        System.out.println("OMGHAI!");
-
-        Item[] items = new Item[] {
-                new Item("+5 Dexterity Vest", 10, 20), //
-                new Item("Aged Brie", 2, 0), //
-                new Item("Elixir of the Mongoose", 5, 7), //
-                new Item("Sulfuras, Hand of Ragnaros", 0, 80), //
-                new Item("Sulfuras, Hand of Ragnaros", -1, 80),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 10, 49),
-                new Item("Backstage passes to a TAFKAL80ETC concert", 5, 49),
-                // this conjured item does not work properly yet
-                new Item("Conjured Mana Cake", 3, 6) };
-
-        GildedRose app = new GildedRose();
-
-        int days = 2;
-        if (args.length > 0) {
-            days = Integer.parseInt(args[0]) + 1;
-        }
-
-        for (int i = 0; i < days; i++) {
-            System.out.println("-------- day " + i + " --------");
-            System.out.println("name, sellIn, quality");
-            for (Item item : items) {
-                System.out.println(item);
-            }
-            System.out.println();
-            app.updateQuality(items);
-        }
-    }
-
-}