Refactored Code- Moved implementation of sellin days and quality to specific classes.

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

@@ -1,5 +1,17 @@
 package com.gildedrose;
 
-public class AgedBrie extends Goods {
+public class AgedBrie implements Goods {
+	private static final int MAX_ALLOWED_QUALITY = 50;
 
+	@Override
+	public void updateQuality(Item item) {
+		addQualityWhenWithInLimit(item);
+
+	}
+
+	private void addQualityWhenWithInLimit(Item item) {
+		if (item.quality < MAX_ALLOWED_QUALITY) {
+			item.quality++;
+		}
+	}
 }

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

@@ -1,5 +1,25 @@
 package com.gildedrose;
 
-public class BackStagePasses extends Goods {
+public class BackStagePasses implements Goods {
+	
+	private static final int MAX_ALLOWED_QUALITY = 50;
+	private static final int SELL_IN_MAX_THRESHOLD_DAY = 11;
+	private static final int SELL_IN_MIN_THRESHOLD_DAY = 6;
 
+	@Override
+	public void updateQuality(Item item) {
+		addQualityWhenWithInLimit(item);
+		if (item.sellIn < SELL_IN_MAX_THRESHOLD_DAY) {
+			addQualityWhenWithInLimit(item);
+		}
+		if (item.sellIn < SELL_IN_MIN_THRESHOLD_DAY) {
+			addQualityWhenWithInLimit(item);
+		}
+	}
+
+	private void addQualityWhenWithInLimit(Item item) {
+		if (item.quality < MAX_ALLOWED_QUALITY) {
+			item.quality++;
+		}
+	}
 }

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

@@ -1,5 +1,10 @@
 package com.gildedrose;
 
-public class Generic extends Goods {
+public class Generic implements Goods {
-
+	@Override
+	public void updateQuality(Item item) {
+		if (item.quality > 0) {
+			item.quality--;
+		}
+	}
 }

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

@@ -1,5 +1,7 @@
 package com.gildedrose;
 
+import com.gildedrose.factory.GoodsFactory;
+
 class GildedRose {
     Item[] items;
 
@@ -9,44 +11,14 @@ class GildedRose {
 
     public void updateQuality() {
 		for (Item item : items) {
-			if (!item.name.equals("Aged Brie")
+			Goods goods = GoodsFactory.getGoods(item.name);
-                    && !item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+			goods.updateQuality(item);
-                if (item.quality > 0) {
+			goods.updateSellInDays(item);
-                    if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-                    	updateQualityForNormalItem(item);
-                    }
-                }
-            } else {
-                if (item.quality < 50) {
-                    item.quality = item.quality + 1;
-
-                    if (item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                        updateQualityForBackstagePasses(item);
-                    }
-                }
-            }
-
-            if (!item.name.equals("Sulfuras, Hand of Ragnaros")) {
-				updateSellInDays(item);
-            }
 
             updateQualityForExpiredItem(item);
         }
     }
 
-	private void updateQualityForBackstagePasses(Item item) {
-		if (item.sellIn < 11) {
-		    addQualityWhenWithInLimit(item);
-		}
-
-		if (item.sellIn < 6) {
-		    addQualityWhenWithInLimit(item);
-		}
-	}
-    
-	private void updateQualityForNormalItem(Item item) {
-		item.quality--;
-	}
 
 	private void addQualityWhenWithInLimit(Item item) {
 		if (item.quality < 50) {
@@ -80,7 +52,4 @@ class GildedRose {
 		item.quality--;
 	}
     
-	private void updateSellInDays(Item item) {
-		item.sellIn--;
-	}
 }

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

@@ -1,5 +1,10 @@
 package com.gildedrose;
 
-public abstract class Goods {
+public interface Goods {
+	
+	public void updateQuality(Item item);
 
+	default void updateSellInDays(Item item) {
+		item.sellIn--;
+	}
 }

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

@@ -1,5 +1,18 @@
 package com.gildedrose;
 
-public class Sulfuras extends Goods {
+public class Sulfuras implements Goods {
+
+	@Override
+	public void updateQuality(Item item) {
+		// Do nothing because Sulfuras being a legendary item, never has to be sold or
+		// decreases in quality.
+
+	}
+
+	@Override
+	public void updateSellInDays(Item item) {
+		// Do nothing because Sulfuras being a legendary item, never has to be sold or
+		// decreases in quality.
+	}
 
 }

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

@@ -0,0 +1,45 @@
+package com.gildedrose;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class AgedBrieTest {
+
+	private static Stream<Arguments> getTestItemsWithExpectedQuality() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.AGED_BRIE.getGoodsName(), 2, 2), 3), 
+				Arguments.of(new Item(GoodsType.AGED_BRIE.getGoodsName(), 1, 50), 50)
+				);
+	}
+	
+	private static Stream<Arguments> getTestItemsWithExpectedSellin() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.AGED_BRIE.getGoodsName(), 2, 2), 1), 
+				Arguments.of(new Item(GoodsType.AGED_BRIE.getGoodsName(), 1, 50), 0)
+				);
+	}
+
+
+	@ParameterizedTest(name = "Test updateQuality - {index}")
+	@MethodSource("getTestItemsWithExpectedQuality")
+	void testUpdateQuality(Item item, int expectedQuality) {
+		AgedBrie agedBrie = new AgedBrie();
+		agedBrie.updateQuality(item);
+		assertEquals(expectedQuality, item.quality);
+	}
+
+	@ParameterizedTest(name = "Test updateSellIn - {index}")
+	@MethodSource("getTestItemsWithExpectedSellin")
+	void testUpdateSellInDaysItem(Item item, int expectedSellin) {
+		AgedBrie agedBrie = new AgedBrie();
+		agedBrie.updateSellInDays(item);
+		assertEquals(expectedSellin, item.sellIn);
+
+	}
+
+}

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

@@ -0,0 +1,48 @@
+package com.gildedrose;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class BackStagePassesTest {
+	private static Stream<Arguments> getTestItemsWithExpectedQuality() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 2, 2), 5),
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 10, 45), 47),
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 0, 49), 50),
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 12, 46), 47),
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 3, 50), 50));
+	}
+	
+	private static Stream<Arguments> getTestItemsWithExpectedSellin() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 2, 2), 1), 
+				Arguments.of(new Item(GoodsType.BACK_STAGE_PASSES.getGoodsName(), 1, 50), 0)
+				);
+	}
+
+
+
+	@ParameterizedTest(name = "Test updateQuality - {index}")
+	@MethodSource("getTestItemsWithExpectedQuality")
+	void testUpdateQuality(Item item, int expectedQuality) {
+		BackStagePasses backStagePasses = new BackStagePasses();
+		backStagePasses.updateQuality(item);
+		assertEquals(expectedQuality, item.quality);
+
+	}
+
+	@ParameterizedTest(name = "Test updateSellIn - {index}")
+	@MethodSource("getTestItemsWithExpectedSellin")
+	void testUpdateSellInDaysItem(Item item, int expectedSellin) {
+		BackStagePasses backStagePasses = new BackStagePasses();
+		backStagePasses.updateSellInDays(item);
+		assertEquals(expectedSellin, item.sellIn);
+
+	}
+
+}

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

@@ -0,0 +1,46 @@
+package com.gildedrose;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class GenericTest {
+
+	private static Stream<Arguments> getTestItemsWithExpectedQuality() {
+		return Stream.of(
+				Arguments.of(new Item("Generic Item", 2, 0), 0), 
+				Arguments.of(new Item("Generic Item", 2, 2), 1)
+				);
+	}
+	
+	private static Stream<Arguments> getTestItemsWithExpectedSellin() {
+		return Stream.of(
+				Arguments.of(new Item("Generic Item", 2, 0), 1), 
+				Arguments.of(new Item("Generic Item", 2, 2), 1)
+				);
+	}
+
+
+
+	@ParameterizedTest(name = "Test updateQuality - {index}")
+	@MethodSource("getTestItemsWithExpectedQuality")
+	void testUpdateQuality(Item item, int expectedQuality) {
+		Generic generic = new Generic();
+		generic.updateQuality(item);
+		assertEquals(expectedQuality, item.quality);
+
+	}
+
+	@ParameterizedTest(name = "Test updateSellIn - {index}")
+	@MethodSource("getTestItemsWithExpectedSellin")
+	void testUpdateSellInDaysItem(Item item, int expectedSellin) {
+		Generic generic = new Generic();
+		generic.updateSellInDays(item);
+		assertEquals(expectedSellin, item.sellIn);
+	}
+
+}

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

@@ -0,0 +1,41 @@
+package com.gildedrose;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class SulfurasTest {
+
+	private static Stream<Arguments> getTestItemsWithExpectedQuality() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.SULFURAS.getGoodsName(), 2, 2), 2),
+				Arguments.of(new Item(GoodsType.SULFURAS.getGoodsName(), 1, 50), 50));
+	}
+
+	private static Stream<Arguments> getTestItemsWithExpectedSellin() {
+		return Stream.of(
+				Arguments.of(new Item(GoodsType.SULFURAS.getGoodsName(), 2, 2), 2),
+				Arguments.of(new Item(GoodsType.SULFURAS.getGoodsName(), 1, 50), 1));
+	}
+
+	@ParameterizedTest(name = "Test updateQuality - {index}")
+	@MethodSource("getTestItemsWithExpectedQuality")
+	void testUpdateQuality(Item item, int expectedQuality) {
+		Sulfuras sulfurus = new Sulfuras();
+		sulfurus.updateQuality(item);
+		assertEquals(expectedQuality, item.quality);
+	}
+
+	@ParameterizedTest(name = "Test updateSellin - {index}")
+	@MethodSource("getTestItemsWithExpectedSellin")
+	void testUpdateSellInDays(Item item, int expectedSellin) {
+		Sulfuras sulfurus = new Sulfuras();
+		sulfurus.updateSellInDays(item);
+		assertEquals(expectedSellin, item.sellIn);
+	}
+
+}