updated kata

Java/build.gradle

@@ -1,5 +1,6 @@
 plugins {
     id 'java'
+    id "io.freefair.lombok" version "6.0.0-m2"
 }
 
 repositories {
@@ -11,6 +12,7 @@ dependencies {
     testImplementation 'org.junit.jupiter:junit-jupiter-params:5.6.2'
     testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.6.2'
     testImplementation 'com.approvaltests:approvaltests:5.0.0'
+    implementation 'org.mockito:mockito-core:3.9.0'
 }
 
 group = 'com.gildedrose'

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

@@ -1,62 +1,24 @@
 package com.gildedrose;
 
-class GildedRose {
-    Item[] items;
+import com.gildedrose.itemsorts.QualityItem;
 
-    public GildedRose(Item[] items) {
+import java.util.ArrayList;
+import java.util.List;
+
+public class GildedRose {
+    private final List<QualityItem> items;
+    private final QualityItemHandler qualityItemHandler;
+
+    public GildedRose(List<QualityItem> items, QualityItemHandler qualityItemHandler) {
         this.items = items;
+        this.qualityItemHandler = qualityItemHandler;
+    }
+
+    public List<QualityItem> getItems() {
+        return new ArrayList<>(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;
-                    }
-                }
-            }
-        }
+        items.replaceAll(qualityItemHandler::processOneItem);
     }
 }

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

@@ -0,0 +1,28 @@
+package com.gildedrose;
+
+
+import com.gildedrose.itemprocessors.ProcessorFactory;
+import com.gildedrose.itemsorts.QualityItem;
+import com.gildedrose.itemtorequest.ProcessingRequestFromQualityItem;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory;
+
+public class QualityItemHandler {
+    private final ProcessorFactory processorFactory;
+    private final ProcessingRequestFromQualityItem processingRequestFromQualityItem;
+    private final QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactory;
+
+    QualityItemHandler(ProcessorFactory processorFactory, ProcessingRequestFromQualityItem processingRequestFromQualityItem,
+                       QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactory) {
+        this.processorFactory = processorFactory;
+        this.processingRequestFromQualityItem = processingRequestFromQualityItem;
+        this.qualityItemFromProcessingResponseFactory = qualityItemFromProcessingResponseFactory;
+    }
+
+    QualityItem processOneItem(QualityItem qualityItem) {
+        return qualityItemFromProcessingResponseFactory.get(qualityItem).toQualityItem(
+                qualityItem,
+                processorFactory.get(qualityItem).
+                        processItem(processingRequestFromQualityItem.get(qualityItem))
+        );
+    }
+}

Java/src/main/java/com/gildedrose/itemprocessors/AgedBrieProcessor.java

@@ -0,0 +1,12 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton;
+
+import com.gildedrose.itemsorts.AgedBrie;
+
+public class AgedBrieProcessor extends QualityItemProcessorSkeleton<AgedBrie> implements QualityItemProcessor<AgedBrie> {
+    @Override
+    int qualityFunction(int oldQuality, int qualityChange) {
+        return oldQuality + qualityChange;
+    }
+}

Java/src/main/java/com/gildedrose/itemprocessors/BackstagePassProcessor.java

@@ -0,0 +1,28 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton;
+import com.gildedrose.itemsorts.BackstagePass;
+
+public class BackstagePassProcessor extends QualityItemProcessorSkeleton<BackstagePass> implements QualityItemProcessor<BackstagePass>{
+
+    public static final int FIVE_DAYS_BEFORE_CONCERT = 5;
+    public static final int TEN_DAYS_BEFORE_CONCERT = 10;
+
+    @Override
+    int qualityFunction(int oldQuality, int qualityChange) {
+        return oldQuality + qualityChange;
+    }
+
+    @Override
+    int calculateQualityChange(int sellIn, int oldQuality) {
+        if (sellIn < 0) {
+            return -oldQuality;
+        } else if (sellIn < FIVE_DAYS_BEFORE_CONCERT) {
+            return 3;
+        } else if (sellIn < TEN_DAYS_BEFORE_CONCERT) {
+            return 2;
+        } else {
+            return 1;
+        }
+    }
+}

Java/src/main/java/com/gildedrose/itemprocessors/ConjuredItemProcessor.java

@@ -0,0 +1,15 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton;
+import com.gildedrose.itemsorts.ConjuredItem;
+
+
+public class ConjuredItemProcessor extends QualityItemProcessorSkeleton<ConjuredItem> implements QualityItemProcessor<ConjuredItem> {
+
+    public static final int CONJURED_ITEM_QUALITY_CHANGE_MULTIPLIER = 2;
+
+    @Override
+    int applyQualityChangeMultiplier(int qualityChange) {
+        return CONJURED_ITEM_QUALITY_CHANGE_MULTIPLIER * qualityChange;
+    }
+}

Java/src/main/java/com/gildedrose/itemprocessors/NormalItemProcessor.java

@@ -0,0 +1,8 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton;
+import com.gildedrose.itemsorts.NormalItem;
+
+
+public class NormalItemProcessor extends QualityItemProcessorSkeleton<NormalItem> implements QualityItemProcessor<NormalItem> {
+}

Java/src/main/java/com/gildedrose/itemprocessors/ProcessorFactory.java

@@ -0,0 +1,37 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemsorts.QualityItem;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+public class ProcessorFactory {
+    static final String EXCEPTION_MESSAGE_TEMPLATE = "Item processor for the item of type %s is not found. Make sure that the factory" +
+            "is configured correctly";
+    private final Map<Class<? extends QualityItem>, QualityItemProcessor<? extends QualityItem>> qualityItemsProcessors = new HashMap<>();
+
+
+    public ProcessorFactory(List<ProcessorFactoryItem<?>> qualityItemProcessors) {
+        qualityItemProcessors.forEach(processorFactoryItem -> qualityItemsProcessors.put(processorFactoryItem.getItemType(),processorFactoryItem.getItemProcessor()));
+    }
+
+    @Getter
+    @AllArgsConstructor
+    public static class ProcessorFactoryItem<T extends QualityItem> {
+        private final Class<T> itemType;
+        private final QualityItemProcessor<T> itemProcessor;
+    }
+
+    public QualityItemProcessor<QualityItem> get(QualityItem qualityItem) {
+        Class<? extends QualityItem> aClass = qualityItem.getClass();
+        QualityItemProcessor<? extends QualityItem> qualityItemProcessor = Optional.ofNullable(qualityItemsProcessors.get(aClass)).orElseThrow(
+                () -> new IllegalArgumentException(String.format(EXCEPTION_MESSAGE_TEMPLATE, aClass)));
+        @SuppressWarnings("unchecked") // unnecessary
+        QualityItemProcessor<QualityItem> qualityItemProcessorCasted = (QualityItemProcessor<QualityItem>) qualityItemProcessor;
+        return qualityItemProcessorCasted;
+    }
+}

Java/src/main/java/com/gildedrose/itemprocessors/QualityItemProcessor.java

@@ -0,0 +1,86 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemsorts.QualityItem;
+import lombok.AllArgsConstructor;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+
+
+public interface QualityItemProcessor<T extends QualityItem> {
+    ProcessingResponse<T> processItem(ProcessingRequest<T> processingRequest);
+
+
+    @EqualsAndHashCode
+    @Getter
+    @AllArgsConstructor
+    class ProcessingResponse<T extends QualityItem> {
+        private final int sellIn;
+        private final int quality;
+    }
+
+    @EqualsAndHashCode
+    @Getter
+    @AllArgsConstructor
+    class ProcessingRequest<T extends QualityItem> {
+        private final int sellIn;
+        private final int quality;
+    }
+
+
+    /**
+     * A skeleton intended for subclassing
+     *
+     * @param <T> - type of the item
+     */
+    abstract class QualityItemProcessorSkeleton<T extends QualityItem> implements QualityItemProcessor<T> {
+        static final int QUALITY_CHANGE_AFTER_SELL_DATE = 2;
+        static final int QUALITY_CHANGE_BEFORE_SELL_DATE = 1;
+        static final int MAX_QUALITY = 50;
+        static final int MIN_QUALITY = 0;
+        public static final int DEFAULT_QUALITY_CHANGE_MULTIPLIER = 1;
+
+
+        @Override
+        public ProcessingResponse<T> processItem(ProcessingRequest<T> processingRequest) {
+            int newSellIn = calculateNewSellIn(processingRequest.getSellIn());
+            int newQuality = calculateNewQuality(newSellIn, processingRequest.getQuality());
+            return new ProcessingResponse<>(newSellIn, newQuality);
+        }
+
+        int calculateNewSellIn(int oldSellIn) {
+            return oldSellIn - 1;
+        }
+
+        int calculateNewQuality(int newSellIn, int oldQuality) {
+            return qualityLimitsCheck(qualityFunction(oldQuality, applyQualityChangeMultiplier(calculateQualityChange(newSellIn, oldQuality))));
+        }
+
+        int qualityFunction(int oldQuality, int qualityChange) {
+            return oldQuality - qualityChange;
+        }
+
+        int applyQualityChangeMultiplier(int qualityChange) {
+            return DEFAULT_QUALITY_CHANGE_MULTIPLIER * qualityChange;
+        }
+
+        int calculateQualityChange(int sellIn, int oldQuality) {
+            if (sellIn < 0) {
+                return QUALITY_CHANGE_AFTER_SELL_DATE;
+            } else {
+                return QUALITY_CHANGE_BEFORE_SELL_DATE;
+            }
+        }
+
+
+        int qualityLimitsCheck(int quality) {
+            if (quality > MAX_QUALITY) {
+                return MAX_QUALITY;
+            } else if (quality < MIN_QUALITY) {
+                return MIN_QUALITY;
+            } else {
+                return quality;
+            }
+        }
+    }
+
+}

Java/src/main/java/com/gildedrose/itemprocessors/SulfurasProcessor.java

@@ -0,0 +1,11 @@
+package com.gildedrose.itemprocessors;
+
+
+import com.gildedrose.itemsorts.Sulfuras;
+
+public class SulfurasProcessor implements QualityItemProcessor<Sulfuras> {
+    @Override
+    public ProcessingResponse<Sulfuras> processItem(ProcessingRequest<Sulfuras> processingRequest) {
+        return new ProcessingResponse<>(processingRequest.getSellIn(), processingRequest.getQuality());
+    }
+}

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

@@ -0,0 +1,10 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.itemsorts.QualityItem.QualityItemSkeleton;
+
+
+public class AgedBrie extends QualityItemSkeleton {
+    public AgedBrie(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+}

Java/src/main/java/com/gildedrose/itemsorts/BackstagePass.java

@@ -0,0 +1,9 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.itemsorts.QualityItem.QualityItemSkeleton;
+
+public class BackstagePass extends QualityItemSkeleton {
+    public BackstagePass(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+}

Java/src/main/java/com/gildedrose/itemsorts/ConjuredItem.java

@@ -0,0 +1,9 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.itemsorts.QualityItem.QualityItemSkeleton;
+
+public class ConjuredItem extends QualityItemSkeleton implements QualityItem {
+    public ConjuredItem(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+}

Java/src/main/java/com/gildedrose/itemsorts/NormalItem.java

@@ -0,0 +1,9 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.itemsorts.QualityItem.QualityItemSkeleton;
+
+public class NormalItem extends QualityItemSkeleton implements QualityItem {
+    public NormalItem(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+}

Java/src/main/java/com/gildedrose/itemsorts/QualityItem.java

@@ -0,0 +1,65 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.Item;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+public interface QualityItem {
+    String getName();
+
+    int getSellIn();
+
+    int getQuality();
+
+    /**
+     * Skeleton class intended for subclassing
+     */
+    abstract class QualityItemSkeleton implements QualityItem {
+        private final Item item;
+
+        public QualityItemSkeleton(String name, int sellIn, int quality) {
+            this.item = new Item(name, sellIn, quality);
+        }
+
+        @Override
+        public String getName() {
+            return item.name;
+        }
+
+        @Override
+        public String toString() {
+            return item.toString();
+        }
+
+        @Override
+        public int getQuality() {
+            return item.quality;
+        }
+
+        @Override
+        public int getSellIn() {
+            return item.sellIn;
+        }
+
+        @Override
+        public boolean equals(Object other) {
+            if (!(other instanceof QualityItem) || other.getClass() != this.getClass()) {
+                return false;
+            }
+            QualityItem qualityItem = (QualityItem) other;
+            return (this.getName().equals(qualityItem.getName())) &&
+                    (this.getQuality() == qualityItem.getQuality()) &&
+                    (this.getSellIn() == qualityItem.getSellIn());
+        }
+
+
+        @Override
+        public int hashCode() {
+            int result = getName() == null ? 0 : getName().hashCode();
+            result += 31 * result + getQuality();
+            result += 31 * result + getSellIn();
+            result += 31 * result + this.getClass().getName().hashCode();
+            return result;
+        }
+    }
+}

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

@@ -0,0 +1,9 @@
+package com.gildedrose.itemsorts;
+
+import com.gildedrose.itemsorts.QualityItem.QualityItemSkeleton;
+
+public class Sulfuras extends QualityItemSkeleton implements QualityItem {
+    public Sulfuras(String name, int sellIn, int quality) {
+        super(name, sellIn, quality);
+    }
+}

Java/src/main/java/com/gildedrose/itemtorequest/ProcessingRequestFromQualityItem.java

@@ -0,0 +1,10 @@
+package com.gildedrose.itemtorequest;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingRequest;
+import com.gildedrose.itemsorts.QualityItem;
+
+public class ProcessingRequestFromQualityItem {
+    public <T extends QualityItem> ProcessingRequest<T> get(T qualityItem) {
+        return new ProcessingRequest<>(qualityItem.getSellIn(), qualityItem.getQuality());
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/AgedBrieFromProcessingResponse.java

@@ -0,0 +1,11 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.AgedBrie;
+
+public class AgedBrieFromProcessingResponse implements QualityItemFromProcessingResponse<AgedBrie> {
+    @Override
+    public AgedBrie toQualityItem(AgedBrie qualityItemOld, ProcessingResponse<AgedBrie> processingResponse) {
+        return new AgedBrie(qualityItemOld.getName(), processingResponse.getSellIn(), processingResponse.getQuality());
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/BackstagePassFromProcessingResponse.java

@@ -0,0 +1,11 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.BackstagePass;
+
+public class BackstagePassFromProcessingResponse implements QualityItemFromProcessingResponse<BackstagePass> {
+    @Override
+    public BackstagePass toQualityItem(BackstagePass qualityItemOld, ProcessingResponse<BackstagePass> processingResponse) {
+        return new BackstagePass(qualityItemOld.getName(), processingResponse.getSellIn(), processingResponse.getQuality());
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/ConjuredItemFromProcessingResponse.java

@@ -0,0 +1,11 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.ConjuredItem;
+
+public class ConjuredItemFromProcessingResponse implements QualityItemFromProcessingResponse<ConjuredItem> {
+    @Override
+    public ConjuredItem toQualityItem(ConjuredItem qualityItemOld, ProcessingResponse<ConjuredItem> processingResponse) {
+        return new ConjuredItem(qualityItemOld.getName(), processingResponse.getSellIn(), processingResponse.getQuality());
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/NormalItemFromProcessingResponse.java

@@ -0,0 +1,12 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.NormalItem;
+
+
+public class NormalItemFromProcessingResponse implements QualityItemFromProcessingResponse<NormalItem> {
+    @Override
+    public NormalItem toQualityItem(NormalItem qualityItemOld, ProcessingResponse<NormalItem> processingResponse) {
+        return new NormalItem(qualityItemOld.getName(), processingResponse.getSellIn(), processingResponse.getQuality());
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/QualityItemFromProcessingResponse.java

@@ -0,0 +1,8 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.QualityItem;
+
+public interface QualityItemFromProcessingResponse<T extends QualityItem> {
+    T toQualityItem(T qualityItemOld, ProcessingResponse<T> processingResponse);
+}

Java/src/main/java/com/gildedrose/responsetoitem/QualityItemFromProcessingResponseFactory.java

@@ -0,0 +1,44 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemsorts.QualityItem;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+public class QualityItemFromProcessingResponseFactory {
+    static final String EXCEPTION_MESSAGE_TEMPLATE = "QualityItemFromProcessingResponse for the item of type %s is not found. Make sure that the factory" +
+            "is configured correctly";
+
+    Map<Class<? extends QualityItem>, QualityItemFromProcessingResponse<? extends QualityItem>> qualityItemFromProcessingResponseMap = new HashMap<>();
+
+    public <T extends QualityItem> QualityItemFromProcessingResponse<T> get(T qualityItem) {
+        Class<? extends QualityItem> aClass = qualityItem.getClass();
+        QualityItemFromProcessingResponse<? extends QualityItem> qualityItemProcessor = Optional.ofNullable(qualityItemFromProcessingResponseMap.get(aClass))
+                .orElseThrow(
+                        () -> new IllegalArgumentException(String.format(EXCEPTION_MESSAGE_TEMPLATE, aClass)));
+        @SuppressWarnings("unchecked")
+        QualityItemFromProcessingResponse<T> qualityItemFromProcessingResponse =
+                (QualityItemFromProcessingResponse<T>) qualityItemProcessor;
+        return qualityItemFromProcessingResponse;
+    }
+
+
+    @Getter
+    @AllArgsConstructor
+    public static class QualityItemFromProcessingResponseFactoryItem<T extends QualityItem> {
+        private final Class<T> itemType;
+        private final QualityItemFromProcessingResponse<T> itemProcessor;
+    }
+
+    public QualityItemFromProcessingResponseFactory(List<QualityItemFromProcessingResponseFactoryItem<?>> qualityItemFromProcessingResponseFactoryItems) {
+        qualityItemFromProcessingResponseFactoryItems.forEach(qualityItemFromProcessingResponseFactoryItem ->
+                qualityItemFromProcessingResponseMap.put(
+                        qualityItemFromProcessingResponseFactoryItem.getItemType(),
+                        qualityItemFromProcessingResponseFactoryItem.getItemProcessor())
+        );
+    }
+}

Java/src/main/java/com/gildedrose/responsetoitem/SulfurasFromProcessingResponse.java

@@ -0,0 +1,11 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.Sulfuras;
+
+public class SulfurasFromProcessingResponse implements QualityItemFromProcessingResponse<Sulfuras> {
+    @Override
+    public Sulfuras toQualityItem(Sulfuras qualityItemOld, ProcessingResponse<Sulfuras> processingResponse) {
+        return new Sulfuras(qualityItemOld.getName(), processingResponse.getSellIn(), processingResponse.getQuality());
+    }
+}

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

@@ -1,17 +1,94 @@
 package com.gildedrose;
 
+import com.gildedrose.itemprocessors.AgedBrieProcessor;
+import com.gildedrose.itemprocessors.BackstagePassProcessor;
+import com.gildedrose.itemprocessors.ConjuredItemProcessor;
+import com.gildedrose.itemprocessors.NormalItemProcessor;
+import com.gildedrose.itemprocessors.ProcessorFactory;
+import com.gildedrose.itemprocessors.ProcessorFactory.ProcessorFactoryItem;
+import com.gildedrose.itemprocessors.SulfurasProcessor;
+import com.gildedrose.itemsorts.AgedBrie;
+import com.gildedrose.itemsorts.BackstagePass;
+import com.gildedrose.itemsorts.ConjuredItem;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import com.gildedrose.itemsorts.Sulfuras;
+import com.gildedrose.itemtorequest.ProcessingRequestFromQualityItem;
+import com.gildedrose.responsetoitem.AgedBrieFromProcessingResponse;
+import com.gildedrose.responsetoitem.BackstagePassFromProcessingResponse;
+import com.gildedrose.responsetoitem.ConjuredItemFromProcessingResponse;
+import com.gildedrose.responsetoitem.NormalItemFromProcessingResponse;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory.QualityItemFromProcessingResponseFactoryItem;
+import com.gildedrose.responsetoitem.SulfurasFromProcessingResponse;
 import org.junit.jupiter.api.Test;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class GildedRoseTest {
 
     @Test
     void foo() {
-        Item[] items = new Item[] { new Item("foo", 0, 0) };
-        GildedRose app = new GildedRose(items);
+        List<QualityItem> items = new ArrayList<>();
+        items.add(new NormalItem("foo", 0, 0));
+
+        List<ProcessorFactoryItem<?>> processorFactoryItems = Arrays.asList(
+                new ProcessorFactoryItem<>(NormalItem.class, new NormalItemProcessor()),
+                new ProcessorFactoryItem<>(AgedBrie.class, new AgedBrieProcessor()),
+                new ProcessorFactoryItem<>(Sulfuras.class, new SulfurasProcessor()),
+                new ProcessorFactoryItem<>(BackstagePass.class, new BackstagePassProcessor()),
+                new ProcessorFactoryItem<>(ConjuredItem.class, new ConjuredItemProcessor()));
+        ProcessorFactory processorFactory = new ProcessorFactory(processorFactoryItems);
+
+        List<QualityItemFromProcessingResponseFactoryItem<?>> qualityItemFromProcessingResponseFactoryItems = Arrays.asList(
+                new QualityItemFromProcessingResponseFactoryItem<>(NormalItem.class, new NormalItemFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(AgedBrie.class, new AgedBrieFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(Sulfuras.class, new SulfurasFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(BackstagePass.class, new BackstagePassFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(ConjuredItem.class, new ConjuredItemFromProcessingResponse()));
+        QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactory =
+                new QualityItemFromProcessingResponseFactory(qualityItemFromProcessingResponseFactoryItems);
+
+        ProcessingRequestFromQualityItem processingRequestFromQualityItem = new ProcessingRequestFromQualityItem();
+
+        QualityItemHandler qualityItemHandler = new QualityItemHandler(processorFactory, processingRequestFromQualityItem,
+                qualityItemFromProcessingResponseFactory);
+
+        GildedRose app = new GildedRose(items, qualityItemHandler);
         app.updateQuality();
-        assertEquals("fixme", app.items[0].name);
+        assertEquals("foo", app.getItems().get(0).getName());
     }
 
+    /**
+     * Check that {@link GildedRose#updateQuality()} will call {@link QualityItemHandler#processOneItem(QualityItem)}
+     * for every element in the GildedRose
+     */
+    @Test
+    void updateQualityTest() {
+        List<QualityItem> calledForItems = new ArrayList<>();
+        List<QualityItem> inputItems = new ArrayList<>();
+        NormalItem expectedItem1 = new NormalItem("name1", 1, 2);
+        NormalItem expectedItem2 = new NormalItem("name2", 1, 2);
+        inputItems.add(expectedItem1);
+        inputItems.add(expectedItem2);
+
+        QualityItemHandler qualityItemHandler = new QualityItemHandler(null, null, null) {
+            @Override
+            QualityItem processOneItem(QualityItem qualityItem) {
+                calledForItems.add(qualityItem);
+                return qualityItem;
+            }
+        };
+        GildedRose gildedRose = new GildedRose(inputItems, qualityItemHandler);
+
+        gildedRose.updateQuality();
+        assertTrue(calledForItems.containsAll(inputItems));
+        calledForItems.removeAll(inputItems);
+        assertTrue(calledForItems.isEmpty());
+    }
 }

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

@@ -0,0 +1,55 @@
+package com.gildedrose;
+
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponse;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory;
+import com.gildedrose.itemprocessors.ProcessorFactory;
+import com.gildedrose.itemprocessors.QualityItemProcessor;
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingRequest;
+import com.gildedrose.itemtorequest.ProcessingRequestFromQualityItem;
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class QualityItemHandlerTest {
+
+    /**
+     * Tests the chain of calls in the {@link QualityItemHandler#processOneItem(QualityItem)} method.
+     */
+    @Test
+    void updateQualityForOneItemTest() {
+        ProcessorFactory processorFactoryMock = Mockito.mock(ProcessorFactory.class);
+        ProcessingRequestFromQualityItem processingRequestFromQualityItemMock = Mockito.mock(ProcessingRequestFromQualityItem.class);
+        QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactoryMock = Mockito.mock(QualityItemFromProcessingResponseFactory.class);
+
+
+        QualityItemHandler qualityItemHandler = new QualityItemHandler(processorFactoryMock, processingRequestFromQualityItemMock, qualityItemFromProcessingResponseFactoryMock);
+        QualityItem qualityItem = new NormalItem("name", 1, 1);
+        QualityItem qualityItemResult = new NormalItem("result", 1, 1);
+
+        ProcessingRequest<QualityItem> expectedProcessingRequest = new ProcessingRequest<>(1, 2);
+        Mockito.when(processingRequestFromQualityItemMock.get(qualityItem)).thenReturn(expectedProcessingRequest);
+
+        @SuppressWarnings("unchecked")
+        QualityItemProcessor<QualityItem> itemProcessorMock = (QualityItemProcessor<QualityItem>) Mockito.mock(QualityItemProcessor.class);
+        Mockito.when(processorFactoryMock.get(qualityItem)).thenReturn(itemProcessorMock);
+
+
+        ProcessingResponse<QualityItem> expectedProcessingResponse = new ProcessingResponse<>(1, 2);
+        Mockito.when(itemProcessorMock.processItem(expectedProcessingRequest)).thenReturn(expectedProcessingResponse);
+
+
+        @SuppressWarnings("unchecked")
+        QualityItemFromProcessingResponse<QualityItem> qualityItemQualityItemFromProcessingResponse =
+                (QualityItemFromProcessingResponse<QualityItem>) Mockito.mock(QualityItemFromProcessingResponse.class);
+        Mockito.when(qualityItemFromProcessingResponseFactoryMock.get(qualityItem)).thenReturn(qualityItemQualityItemFromProcessingResponse);
+
+        Mockito.when(qualityItemQualityItemFromProcessingResponse.toQualityItem(qualityItem, expectedProcessingResponse))
+                .thenReturn(qualityItemResult);
+
+        assertEquals(qualityItemResult, qualityItemHandler.processOneItem(qualityItem));
+    }
+}

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

@@ -1,22 +1,70 @@
 package com.gildedrose;
 
+import com.gildedrose.responsetoitem.AgedBrieFromProcessingResponse;
+import com.gildedrose.responsetoitem.BackstagePassFromProcessingResponse;
+import com.gildedrose.responsetoitem.ConjuredItemFromProcessingResponse;
+import com.gildedrose.responsetoitem.NormalItemFromProcessingResponse;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory;
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory.QualityItemFromProcessingResponseFactoryItem;
+import com.gildedrose.responsetoitem.SulfurasFromProcessingResponse;
+import com.gildedrose.itemprocessors.AgedBrieProcessor;
+import com.gildedrose.itemprocessors.BackstagePassProcessor;
+import com.gildedrose.itemprocessors.ConjuredItemProcessor;
+import com.gildedrose.itemprocessors.NormalItemProcessor;
+import com.gildedrose.itemprocessors.ProcessorFactory;
+import com.gildedrose.itemprocessors.ProcessorFactory.ProcessorFactoryItem;
+import com.gildedrose.itemtorequest.ProcessingRequestFromQualityItem;
+import com.gildedrose.itemprocessors.SulfurasProcessor;
+import com.gildedrose.itemsorts.AgedBrie;
+import com.gildedrose.itemsorts.BackstagePass;
+import com.gildedrose.itemsorts.ConjuredItem;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import com.gildedrose.itemsorts.Sulfuras;
+
+import java.util.Arrays;
+import java.util.List;
+
 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),
+        List<QualityItem> items = Arrays.asList(
+                new NormalItem("+5 Dexterity Vest", 10, 20), //
+                new AgedBrie("Aged Brie", 2, 0), //
+                new NormalItem("Elixir of the Mongoose", 5, 7), //
+                new Sulfuras("Sulfuras, Hand of Ragnaros", 0, 80), //
+                new Sulfuras("Sulfuras, Hand of Ragnaros", -1, 80),
+                new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 15, 20),
+                new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 10, 49),
+                new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 5, 49),
                 // this conjured item does not work properly yet
-                new Item("Conjured Mana Cake", 3, 6) };
+                new ConjuredItem("Conjured Mana Cake", 3, 6)
+        );
 
-        GildedRose app = new GildedRose(items);
+        List<ProcessorFactoryItem<?>> processorFactoryItems = Arrays.asList(
+                new ProcessorFactoryItem<>(NormalItem.class, new NormalItemProcessor()),
+                new ProcessorFactoryItem<>(AgedBrie.class, new AgedBrieProcessor()),
+                new ProcessorFactoryItem<>(Sulfuras.class, new SulfurasProcessor()),
+                new ProcessorFactoryItem<>(BackstagePass.class, new BackstagePassProcessor()),
+                new ProcessorFactoryItem<>(ConjuredItem.class, new ConjuredItemProcessor()));
+        ProcessorFactory processorFactory = new ProcessorFactory(processorFactoryItems);
+
+        List<QualityItemFromProcessingResponseFactoryItem<?>> qualityItemFromProcessingResponseFactoryItems = Arrays.asList(
+                new QualityItemFromProcessingResponseFactoryItem<>(NormalItem.class, new NormalItemFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(AgedBrie.class, new AgedBrieFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(Sulfuras.class, new SulfurasFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(BackstagePass.class, new BackstagePassFromProcessingResponse()),
+                new QualityItemFromProcessingResponseFactoryItem<>(ConjuredItem.class, new ConjuredItemFromProcessingResponse()));
+        QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactory =
+                new QualityItemFromProcessingResponseFactory(qualityItemFromProcessingResponseFactoryItems);
+
+        ProcessingRequestFromQualityItem processingRequestFromQualityItem = new ProcessingRequestFromQualityItem();
+
+        QualityItemHandler qualityItemHandler = new QualityItemHandler(processorFactory, processingRequestFromQualityItem,
+                qualityItemFromProcessingResponseFactory);
+
+        GildedRose app = new GildedRose(items, qualityItemHandler);
 
         int days = 2;
         if (args.length > 0) {
@@ -26,7 +74,7 @@ public class TexttestFixture {
         for (int i = 0; i < days; i++) {
             System.out.println("-------- day " + i + " --------");
             System.out.println("name, sellIn, quality");
-            for (Item item : items) {
+            for (QualityItem item : items) {
                 System.out.println(item);
             }
             System.out.println();

Java/src/test/java/com/gildedrose/itemprocessors/AgedBrieProcessorTest.java

@@ -0,0 +1,15 @@
+package com.gildedrose.itemprocessors;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class AgedBrieProcessorTest {
+    @Test
+    public void test(){
+        AgedBrieProcessor agedBrieProcessor = new AgedBrieProcessor();
+        int oldQuality = 3;
+        int qualityChange = 4;
+        assertEquals(oldQuality + qualityChange, agedBrieProcessor.qualityFunction(oldQuality, qualityChange));
+    }
+}

Java/src/test/java/com/gildedrose/itemprocessors/BackstagePassProcessorTest.java

@@ -0,0 +1,38 @@
+package com.gildedrose.itemprocessors;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static com.gildedrose.itemprocessors.BackstagePassProcessor.FIVE_DAYS_BEFORE_CONCERT;
+import static com.gildedrose.itemprocessors.BackstagePassProcessor.TEN_DAYS_BEFORE_CONCERT;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class BackstagePassProcessorTest {
+    @Test
+    public void test() {
+        BackstagePassProcessor backstagePassProcessor = new BackstagePassProcessor();
+        int oldQuality = 33;
+        int newQuality = 88;
+        assertEquals(oldQuality + newQuality, backstagePassProcessor.qualityFunction(oldQuality, newQuality));
+    }
+
+    @SuppressWarnings("unused")
+    public static Stream<Arguments> calculateQualityChangeValues() {
+        return Stream.of(
+               Arguments.of(-1, 77, -77) ,
+               Arguments.of(FIVE_DAYS_BEFORE_CONCERT - 1, 77, 3),
+               Arguments.of(TEN_DAYS_BEFORE_CONCERT - 1, 77, 2),
+               Arguments.of(TEN_DAYS_BEFORE_CONCERT, 77, 1)
+        );
+    }
+    @MethodSource("calculateQualityChangeValues")
+    @ParameterizedTest
+    public void calculateQualityChangeTest(int sellIn, int oldQuality, int expectedQualityChange) {
+        BackstagePassProcessor backstagePassProcessor = new BackstagePassProcessor();
+        assertEquals(expectedQualityChange, backstagePassProcessor.calculateQualityChange(sellIn, oldQuality));
+    }
+}

Java/src/test/java/com/gildedrose/itemprocessors/ConjuredItemProcessorTest.java

@@ -0,0 +1,17 @@
+package com.gildedrose.itemprocessors;
+
+import org.junit.jupiter.api.Test;
+
+import static com.gildedrose.itemprocessors.ConjuredItemProcessor.CONJURED_ITEM_QUALITY_CHANGE_MULTIPLIER;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ConjuredItemProcessorTest {
+
+    @Test
+    void calculateQualityChange() {
+        ConjuredItemProcessor conjuredItemProcessor = new ConjuredItemProcessor();
+        int qualityChange = 77;
+        assertEquals(qualityChange * CONJURED_ITEM_QUALITY_CHANGE_MULTIPLIER,
+                conjuredItemProcessor.applyQualityChangeMultiplier(qualityChange));
+    }
+}

Java/src/test/java/com/gildedrose/itemprocessors/ProcessorFactoryTest.java

@@ -0,0 +1,39 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.ProcessorFactory.ProcessorFactoryItem;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+
+import java.util.Collections;
+
+import static com.gildedrose.itemprocessors.ProcessorFactory.EXCEPTION_MESSAGE_TEMPLATE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class ProcessorFactoryTest {
+
+    @Test
+    public void testFactoryCannotHandleItem() {
+        ProcessorFactory processorFactory = new ProcessorFactory(Collections.emptyList());
+        QualityItem itemThatCannotBeProcessed = Mockito.mock(QualityItem.class);
+        boolean exceptionWasThrown = false;
+        try {
+            processorFactory.get(itemThatCannotBeProcessed);
+        } catch (IllegalArgumentException e) {
+            exceptionWasThrown = true;
+            assertEquals(String.format(EXCEPTION_MESSAGE_TEMPLATE, itemThatCannotBeProcessed.getClass()), e.getMessage());
+        }
+        assertTrue(exceptionWasThrown);
+    }
+
+    @Test
+    public void testFactoryCanHandleItem() {
+        QualityItemProcessor<NormalItem> normalItemProcessor = new NormalItemProcessor();
+        NormalItem normalItem = new NormalItem("name", 1, 2);
+        ProcessorFactory processorFactory = new ProcessorFactory(Collections.singletonList(new ProcessorFactoryItem<>(NormalItem.class, normalItemProcessor)));
+        assertEquals(normalItemProcessor, processorFactory.get(normalItem));
+    }
+}

Java/src/test/java/com/gildedrose/itemprocessors/QualityItemProcessorTest.java

@@ -0,0 +1,142 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingRequest;
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton.MAX_QUALITY;
+import static com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton.MIN_QUALITY;
+import static com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton.QUALITY_CHANGE_AFTER_SELL_DATE;
+import static com.gildedrose.itemprocessors.QualityItemProcessor.QualityItemProcessorSkeleton.QUALITY_CHANGE_BEFORE_SELL_DATE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class QualityItemProcessorTest {
+
+
+    @Test
+    public void testCalculateItem() {
+        final int oldQualityExpected = 3;
+        final int oldSellInExpected = 27;
+        final int newSellInExpected = 509;
+        final int newQualityExpected = 99;
+        NormalItem testItem = new NormalItem("test item", oldSellInExpected, oldQualityExpected);
+
+        ProcessingRequest<QualityItem> qualityItemProcessingRequest = new ProcessingRequest<>(testItem.getSellIn(), testItem.getQuality());
+        ProcessingResponse<QualityItem> qualityItemProcessingResponse = new ProcessingResponse<>(newSellInExpected, newQualityExpected);
+
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {
+            @Override
+            int calculateNewSellIn(int oldSellIn) {
+                assertEquals(oldSellInExpected, oldSellIn);
+                return newSellInExpected;
+            }
+
+            @Override
+            int calculateNewQuality(int newSellIn, int oldQuality) {
+                assertEquals(oldQualityExpected, oldQuality);
+                assertEquals(newSellInExpected, newSellIn);
+                return newQualityExpected;
+            }
+        };
+        assertEquals(qualityItemProcessingResponse, qualityItemProcessorSkeleton.processItem(qualityItemProcessingRequest));
+    }
+
+    @Test
+    public void calculateNewSellInTest() {
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {
+        };
+        int oldSellIn = 1;
+        assertEquals(0, qualityItemProcessorSkeleton.calculateNewSellIn(oldSellIn));
+    }
+
+    @Test
+    public void calculateNewQuality() {
+        int oldQualityExpected = 3;
+        int newSellInExpected = 4;
+        int qualityChangeExpected = 77;
+        int resultOfQualityFunctionExpected = 300;
+        int qualityLimitsCheckExpected = 777;
+        int qualityChangeAfterQualityChangeMultiplierWasApplied = 389;
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {
+            @Override
+            int calculateQualityChange(int sellIn, int oldQuality) {
+                assertEquals(oldQualityExpected, oldQuality);
+                assertEquals(newSellInExpected, sellIn);
+                return qualityChangeExpected;
+            }
+
+            @Override
+            int applyQualityChangeMultiplier(int qualityChange) {
+                assertEquals(qualityChangeExpected, qualityChange);
+                return qualityChangeAfterQualityChangeMultiplierWasApplied;
+            }
+
+            @Override
+            int qualityFunction(int oldQuality, int qualityChange) {
+                assertEquals(oldQualityExpected, oldQuality);
+                assertEquals(qualityChangeAfterQualityChangeMultiplierWasApplied, qualityChange);
+                return resultOfQualityFunctionExpected;
+            }
+
+
+            @Override
+            int qualityLimitsCheck(int quality) {
+                assertEquals(resultOfQualityFunctionExpected, quality);
+                return qualityLimitsCheckExpected;
+            }
+        };
+
+        assertEquals(qualityLimitsCheckExpected, qualityItemProcessorSkeleton.calculateNewQuality(newSellInExpected, oldQualityExpected));
+    }
+
+    @SuppressWarnings("unused")
+    public static Stream<Arguments> qualityChangeTestValues() {
+        return Stream.of(
+                Arguments.of(-1, QUALITY_CHANGE_AFTER_SELL_DATE),
+                Arguments.of(0, QUALITY_CHANGE_BEFORE_SELL_DATE)
+        );
+    }
+
+    @MethodSource("qualityChangeTestValues")
+    @ParameterizedTest
+    public void calculateQualityChangeTest(int sellIn, int expectedChange) {
+        int oldQuality = 333;
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {};
+        assertEquals(expectedChange, qualityItemProcessorSkeleton.calculateQualityChange(sellIn, oldQuality));
+    }
+
+    @Test
+    void testQualityFunctionTest() {
+        int oldQuality = 333;
+        int qualityChange = 77;
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {};
+        assertEquals(oldQuality - qualityChange, qualityItemProcessorSkeleton.qualityFunction(oldQuality, qualityChange));
+    }
+
+    @SuppressWarnings("unused")
+    public static Stream<Arguments> qualityLimitCheckValues() {
+        int between_max_and_min = (MAX_QUALITY + MIN_QUALITY) / 2;
+        return Stream.of(
+                Arguments.of(MAX_QUALITY + 1, MAX_QUALITY),
+                Arguments.of(MIN_QUALITY - 1, MIN_QUALITY),
+                Arguments.of(between_max_and_min, between_max_and_min)
+        );
+    }
+
+    @MethodSource("qualityLimitCheckValues")
+    @ParameterizedTest
+    void qualityLimitsCheckTest(int quality, int resultingQuality) {
+        QualityItemProcessorSkeleton<QualityItem> qualityItemProcessorSkeleton = new QualityItemProcessorSkeleton<QualityItem>() {};
+        assertEquals(resultingQuality, qualityItemProcessorSkeleton.qualityLimitsCheck(quality));
+    }
+
+
+}

Java/src/test/java/com/gildedrose/itemprocessors/SulfurasProcessorTest.java

@@ -0,0 +1,19 @@
+package com.gildedrose.itemprocessors;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingRequest;
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.Sulfuras;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class SulfurasProcessorTest {
+    @Test
+    void processItem() {
+        SulfurasProcessor sulfurasProcessor = new SulfurasProcessor();
+        ProcessingRequest<Sulfuras> sulfurasProcessingRequest = new ProcessingRequest<>(3, 4);
+        ProcessingResponse<Sulfuras> sulfurasProcessingResponse = sulfurasProcessor.processItem(sulfurasProcessingRequest);
+        assertEquals(sulfurasProcessingRequest.getSellIn(), sulfurasProcessingResponse.getSellIn());
+        assertEquals(sulfurasProcessingRequest.getQuality(), sulfurasProcessingResponse.getQuality());
+    }
+}

Java/src/test/java/com/gildedrose/itemtorequest/ProcessingRequestFromQualityItemTest.java

@@ -0,0 +1,19 @@
+package com.gildedrose.itemtorequest;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingRequest;
+import com.gildedrose.itemsorts.NormalItem;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ProcessingRequestFromQualityItemTest {
+    @Test
+    void get() {
+        ProcessingRequestFromQualityItem processingRequestFromQualityItem = new ProcessingRequestFromQualityItem();
+        int sellIn = 99;
+        int quality = 938;
+        NormalItem normalItem = new NormalItem("name", sellIn, quality);
+        ProcessingRequest<NormalItem> expectedProcessingRequest = new ProcessingRequest<>(sellIn, quality);
+        assertEquals(expectedProcessingRequest, processingRequestFromQualityItem.get(normalItem));
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/AgedBrieFromProcessingResponseTest.java

@@ -0,0 +1,21 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.AgedBrie;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class AgedBrieFromProcessingResponseTest {
+
+    @Test
+    void toQualityItem() {
+        AgedBrieFromProcessingResponse agedBrieFromProcessingResponse = new AgedBrieFromProcessingResponse();
+        AgedBrie oldItem = new AgedBrie("name", 1, 2);
+        ProcessingResponse<AgedBrie> processingResponse = new ProcessingResponse<>(7, 8);
+        AgedBrie newItem = agedBrieFromProcessingResponse.toQualityItem(oldItem, processingResponse);
+        assertEquals(oldItem.getName(), newItem.getName());
+        assertEquals(processingResponse.getSellIn(), newItem.getSellIn());
+        assertEquals(processingResponse.getQuality(), newItem.getQuality());
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/BackstagePassFromProcessingResponseTest.java

@@ -0,0 +1,21 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.BackstagePass;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class BackstagePassFromProcessingResponseTest {
+
+    @Test
+    void toQualityItem() {
+        BackstagePassFromProcessingResponse qualityItemFromProcessingResponse = new BackstagePassFromProcessingResponse();
+        BackstagePass oldItem = new BackstagePass("name", 1, 2);
+        ProcessingResponse<BackstagePass> processingResponse = new ProcessingResponse<>(7, 8);
+        BackstagePass newItem = qualityItemFromProcessingResponse.toQualityItem(oldItem, processingResponse);
+        assertEquals(oldItem.getName(), newItem.getName());
+        assertEquals(processingResponse.getSellIn(), newItem.getSellIn());
+        assertEquals(processingResponse.getQuality(), newItem.getQuality());
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/ConjuredItemFromProcessingResponseTest.java

@@ -0,0 +1,21 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.ConjuredItem;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ConjuredItemFromProcessingResponseTest {
+
+    @Test
+    void toQualityItem() {
+        ConjuredItemFromProcessingResponse qualityItemFromProcessingResponse = new ConjuredItemFromProcessingResponse();
+        ConjuredItem oldItem = new ConjuredItem("name", 1, 2);
+        ProcessingResponse<ConjuredItem> processingResponse = new ProcessingResponse<>(7, 8);
+        ConjuredItem newItem = qualityItemFromProcessingResponse.toQualityItem(oldItem, processingResponse);
+        assertEquals(oldItem.getName(), newItem.getName());
+        assertEquals(processingResponse.getSellIn(), newItem.getSellIn());
+        assertEquals(processingResponse.getQuality(), newItem.getQuality());
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/NormalItemFromProcessingResponseTest.java

@@ -0,0 +1,21 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.NormalItem;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class NormalItemFromProcessingResponseTest {
+
+    @Test
+    void toQualityItem() {
+        NormalItemFromProcessingResponse qualityItemFromProcessingResponse = new NormalItemFromProcessingResponse();
+        NormalItem oldItem = new NormalItem("name", 1, 2);
+        ProcessingResponse<NormalItem> processingResponse = new ProcessingResponse<>(7, 8);
+        NormalItem newItem = qualityItemFromProcessingResponse.toQualityItem(oldItem, processingResponse);
+        assertEquals(oldItem.getName(), newItem.getName());
+        assertEquals(processingResponse.getSellIn(), newItem.getSellIn());
+        assertEquals(processingResponse.getQuality(), newItem.getQuality());
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/QualityItemFromProcessingResponseFactoryTest.java

@@ -0,0 +1,40 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory.QualityItemFromProcessingResponseFactoryItem;
+import com.gildedrose.itemsorts.NormalItem;
+import com.gildedrose.itemsorts.QualityItem;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import java.util.Collections;
+
+import static com.gildedrose.responsetoitem.QualityItemFromProcessingResponseFactory.EXCEPTION_MESSAGE_TEMPLATE;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class QualityItemFromProcessingResponseFactoryTest {
+    @Test
+    public void testFactoryCannotHandleAnItem() {
+        QualityItemFromProcessingResponseFactory factory = new QualityItemFromProcessingResponseFactory(Collections.emptyList());
+        QualityItem itemThatCannotBeProcessed = Mockito.mock(QualityItem.class);
+        boolean exceptionWasThrown = false;
+        try {
+            factory.get(itemThatCannotBeProcessed);
+        } catch (IllegalArgumentException e) {
+            exceptionWasThrown = true;
+            assertEquals(String.format(EXCEPTION_MESSAGE_TEMPLATE, itemThatCannotBeProcessed.getClass()), e.getMessage());
+        }
+        assertTrue(exceptionWasThrown);
+    }
+
+    @Test
+    public void testFactoryCanHandleAnItem() {
+        QualityItemFromProcessingResponse<NormalItem> normalItemProcessor = new NormalItemFromProcessingResponse();
+        NormalItem normalItem = new NormalItem("name", 1, 2);
+        QualityItemFromProcessingResponseFactory qualityItemFromProcessingResponseFactory =
+                new QualityItemFromProcessingResponseFactory(Collections.singletonList(
+                        new QualityItemFromProcessingResponseFactoryItem<>(NormalItem.class, normalItemProcessor)
+                ));
+        assertEquals(normalItemProcessor, qualityItemFromProcessingResponseFactory.get(normalItem));
+    }
+}

Java/src/test/java/com/gildedrose/responsetoitem/SulfurasFromProcessingResponseTest.java

@@ -0,0 +1,21 @@
+package com.gildedrose.responsetoitem;
+
+import com.gildedrose.itemprocessors.QualityItemProcessor.ProcessingResponse;
+import com.gildedrose.itemsorts.Sulfuras;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class SulfurasFromProcessingResponseTest {
+
+    @Test
+    void toQualityItem() {
+        SulfurasFromProcessingResponse qualityItemFromProcessingResponse = new SulfurasFromProcessingResponse();
+        Sulfuras oldItem = new Sulfuras("name", 1, 2);
+        ProcessingResponse<Sulfuras> processingResponse = new ProcessingResponse<>(7, 8);
+        Sulfuras newItem = qualityItemFromProcessingResponse.toQualityItem(oldItem, processingResponse);
+        assertEquals(oldItem.getName(), newItem.getName());
+        assertEquals(processingResponse.getSellIn(), newItem.getSellIn());
+        assertEquals(processingResponse.getQuality(), newItem.getQuality());
+    }
+}

texttests/ThirtyDays/stdout.gr

@@ -21,7 +21,7 @@ Sulfuras, Hand of Ragnaros, -1, 80
 Backstage passes to a TAFKAL80ETC concert, 14, 21
 Backstage passes to a TAFKAL80ETC concert, 9, 50
 Backstage passes to a TAFKAL80ETC concert, 4, 50
-Conjured Mana Cake, 2, 5
+Conjured Mana Cake, 2, 4
 
 -------- day 2 --------
 name, sellIn, quality
@@ -33,7 +33,7 @@ Sulfuras, Hand of Ragnaros, -1, 80
 Backstage passes to a TAFKAL80ETC concert, 13, 22
 Backstage passes to a TAFKAL80ETC concert, 8, 50
 Backstage passes to a TAFKAL80ETC concert, 3, 50
-Conjured Mana Cake, 1, 4
+Conjured Mana Cake, 1, 2
 
 -------- day 3 --------
 name, sellIn, quality
@@ -45,7 +45,7 @@ Sulfuras, Hand of Ragnaros, -1, 80
 Backstage passes to a TAFKAL80ETC concert, 12, 23
 Backstage passes to a TAFKAL80ETC concert, 7, 50
 Backstage passes to a TAFKAL80ETC concert, 2, 50
-Conjured Mana Cake, 0, 3
+Conjured Mana Cake, 0, 0
 
 -------- day 4 --------
 name, sellIn, quality
@@ -57,7 +57,7 @@ Sulfuras, Hand of Ragnaros, -1, 80
 Backstage passes to a TAFKAL80ETC concert, 11, 24
 Backstage passes to a TAFKAL80ETC concert, 6, 50
 Backstage passes to a TAFKAL80ETC concert, 1, 50
-Conjured Mana Cake, -1, 1
+Conjured Mana Cake, -1, 0
 
 -------- day 5 --------
 name, sellIn, quality

texttests/config.gr

@@ -1,4 +1,5 @@
 full_name:Gilded Rose Refactoring Kata
+home_operating_system:posix
 
 # set your preferred editor and diff tool.
 view_program:subl
@@ -12,8 +13,8 @@ diff_program:meld
 #executable:${TEXTTEST_HOME}/cpp/cmake-build-debug/test/cpp_texttest/GildedRoseTextTests
 
 # Settings for the Java version
-#executable:com.gildedrose.TexttestFixture
-#interpreter:java
+executable:com.gildedrose.TexttestFixture
+interpreter:java
 # note you'll also need to update the file environment.gr with your classpath if you keep your classfiles somewhere unusual
 
 # Settings for the Ruby version