Deliver simple, min and advanced implementations. Also test that proves each implementation works as expected

Kotlin/README.md

@@ -64,4 +64,16 @@ During refactor I also found README file in a main directory in which algorithm
 - quality cannot be negative
 
 At this point code is readable but not so extensible because all algos are in a single class which might grow to infinity.
-The usual way to handle this situation is to go with OO approach - I cannot modify Item class so I will implement new one and its specifications.
+The usual way to handle this situation is to go with OO approach - I cannot modify Item class so I will implement new one and its specifications.
+
+### End result
+I didn't modify gliderose in order to be able to execute regression tests that compare my new implementation results with original.
+I created a package platinumrose with few subpackages
+- simple: is the simpleness, cleaned up implementation, no OO concepts or design-patterns
+- mid: is the mid-level implementation with a separate strategies for each type of item
+- advanced - is one of possible implementation of production grade code, it involves item extension methods, qualityCalculator factory, and separation of concepts. This is the only impl fuully covered by tests
+![img_2.png](img_2.png)
+
+
+### TODO
+- I didn't cover extra case described in the main README because of other responsibilities and lack of time

Kotlin/src/main/kotlin/com/gildedrose/Item.kt

@@ -1,5 +1,6 @@
 package com.gildedrose
 
+// NOTE: changes to data class to make comparison (asserts) easier. If rough goblin is against it, I'm ready to die
 data class Item(var name: String, var sellIn: Int, var quality: Int) {
     override fun toString(): String {
         return this.name + ", " + this.sellIn + ", " + this.quality

Kotlin/src/main/kotlin/com/gildedrose/ItemExtention.kt

@@ -0,0 +1,2 @@
+package com.gildedrose
+

Kotlin/src/main/kotlin/com/gildedrose/TestcasesGenerator.kt

@@ -1,8 +1,6 @@
 package com.gildedrose
 
-import com.gildedrose.PlatinumRose.Companion.AGED_BRIE
+
-import com.gildedrose.PlatinumRose.Companion.BACKSTAGE_PASSES
-import com.gildedrose.PlatinumRose.Companion.LULFURAS_HAND_OF_RAGNAROK
 import java.util.*
 
 
@@ -20,9 +18,9 @@ fun generateTestCasesInRanger(names: List<String>, sellInRange: IntRange, qualit
 
 fun main(args: Array<String>) {
     val names = listOf(
-        AGED_BRIE,
+        com.platinumrose.ItemType.AGED_BRIE.name,
-        BACKSTAGE_PASSES,
+        com.platinumrose.ItemType.BACKSTAGE_PASSES.name,
-        LULFURAS_HAND_OF_RAGNAROK,
+        com.platinumrose.ItemType.SULFURAS.name,
         "new none-existing on code name"
     )
     val sellInRange = -100..100

Kotlin/src/main/kotlin/com/platinumrose/ItemConstant.kt

@@ -0,0 +1,9 @@
+package com.platinumrose
+
+class ItemConstant {
+    companion object {
+        const val MIN_QUALITY = 0
+        const val REGULAR_ITEM_MAX_QUALITY = 50
+        const val LEGENDARY_ITEM_MAX_QUALITY = 80
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/ItemType.kt

@@ -0,0 +1,14 @@
+package com.platinumrose
+
+enum class ItemType(val value: String? = null) {
+    AGED_BRIE("Aged Brie"),
+    BACKSTAGE_PASSES("Backstage passes to a TAFKAL80ETC concert"),
+    SULFURAS("Sulfuras, Hand of Ragnaros"),
+    REGULAR;
+
+    companion object {
+        fun fromValue(value: String): com.platinumrose.ItemType {
+            return entries.find { it.value == value } ?: com.platinumrose.ItemType.REGULAR
+        }
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/Solution.kt

@@ -0,0 +1,8 @@
+package com.platinumrose
+
+import com.gildedrose.Item
+
+interface Solution {
+    fun items(): List<Item>
+    fun updateQuality()
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/AdvancePlatinumRose.kt

@@ -0,0 +1,23 @@
+package com.platinumrose.advance
+
+import com.gildedrose.Item
+import com.platinumrose.ItemType.Companion.fromValue
+import com.platinumrose.Solution
+import com.platinumrose.advance.extention.updateQuality
+import com.platinumrose.advance.factory.QualityCalculatorFactory
+import com.platinumrose.advance.factory.QualityCalculatorFactoryImpl
+
+class AdvancePlatinumRose(private val items: List<Item>) : Solution {
+
+    private val qualityCalculatorFactory: QualityCalculatorFactory = QualityCalculatorFactoryImpl()
+
+    override fun items(): List<Item> {
+        return items
+    }
+
+    override fun updateQuality() {
+        items.forEach {
+            it.updateQuality(qualityCalculatorFactory.qualityCalculator(fromValue(it.name)))
+        }
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/extention/ItemExtention.kt

@@ -0,0 +1,28 @@
+package com.platinumrose.advance.extention
+
+import com.gildedrose.Item
+import com.platinumrose.advance.quality.QualityCalculator
+
+
+fun Item.updateQuality(qualityCalculator: QualityCalculator) {
+    updateQualityBeforeSellInDate(qualityCalculator)
+    updateQualityAfterSellInDate(qualityCalculator)
+    coerceQuality(qualityCalculator)
+}
+
+private fun Item.updateQualityBeforeSellInDate(qualityCalculator: QualityCalculator) {
+    val qualityIncrease =
+        qualityCalculator.computeQualityIncreaseBeforeSellIn(sellIn, quality)
+    sellIn += qualityCalculator.computeSellInDecrease(sellIn)
+    quality += qualityIncrease
+}
+
+private fun Item.updateQualityAfterSellInDate(qualityCalculator: QualityCalculator) {
+    val qualityIncrease =
+        if (sellIn >= 0) 0 else qualityCalculator.computeQualityIncreaseAfterSellIn(sellIn, quality)
+    quality += qualityIncrease
+}
+
+private fun Item.coerceQuality(qualityCalculator: QualityCalculator) {
+    quality = quality.coerceIn(com.platinumrose.ItemConstant.MIN_QUALITY, qualityCalculator.maxQuality())
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/factory/QualityCalculatorFactory.kt

@@ -0,0 +1,9 @@
+package com.platinumrose.advance.factory
+
+import com.platinumrose.ItemType
+import com.platinumrose.advance.quality.QualityCalculator
+
+
+interface QualityCalculatorFactory {
+    fun qualityCalculator(itemType: ItemType): QualityCalculator
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/factory/QualityCalculatorFactoryImpl.kt

@@ -0,0 +1,22 @@
+package com.platinumrose.advance.factory
+
+import com.platinumrose.ItemType
+import com.platinumrose.advance.quality.*
+
+
+class QualityCalculatorFactoryImpl : QualityCalculatorFactory {
+    private val strategies: Map<ItemType, QualityCalculator>
+    private val regularItem = RegularItem()
+
+    init {
+        val agedBrieUpdated = AgedBrie()
+        val backstagePasses = BackstagePasses()
+        val sulfuras = Sulfuras()
+        val strategiesList = listOf(agedBrieUpdated, backstagePasses, sulfuras)
+        strategies = strategiesList.associateBy { it.type() }
+    }
+
+    override fun qualityCalculator(itemType: ItemType): QualityCalculator {
+        return strategies.getOrDefault(itemType, regularItem)
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/quality/AgedBrie.kt

@@ -0,0 +1,28 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.AGED_BRIE
+
+
+internal class AgedBrie : QualityCalculator {
+
+    override fun type(): com.platinumrose.ItemType {
+        return AGED_BRIE
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+
+    override fun computeSellInDecrease(sellIn: Int): Int {
+        return -1
+    }
+
+    override fun computeQualityIncreaseBeforeSellIn(sellIn: Int, quality: Int): Int {
+        return 1
+    }
+
+    override fun computeQualityIncreaseAfterSellIn(sellIn: Int, quality: Int): Int {
+        return 1
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/quality/BackstagePasses.kt

@@ -0,0 +1,32 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.BACKSTAGE_PASSES
+
+
+internal class BackstagePasses : QualityCalculator {
+
+    override fun type(): com.platinumrose.ItemType {
+        return BACKSTAGE_PASSES
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+
+    override fun computeSellInDecrease(sellIn: Int): Int {
+        return -1
+    }
+
+    override fun computeQualityIncreaseBeforeSellIn(sellIn: Int, quality: Int): Int {
+        return when (sellIn) {
+            in 0..5 -> 3
+            in 6..10 -> 2
+            else -> 1
+        }
+    }
+
+    override fun computeQualityIncreaseAfterSellIn(sellIn: Int, quality: Int): Int {
+        return -quality
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/quality/QualityCalculator.kt

@@ -0,0 +1,11 @@
+package com.platinumrose.advance.quality
+
+interface QualityCalculator {
+
+    fun type(): com.platinumrose.ItemType
+    fun maxQuality(): Int
+
+    fun computeQualityIncreaseBeforeSellIn(sellIn: Int, quality: Int): Int;
+    fun computeSellInDecrease(sellIn: Int): Int
+    fun computeQualityIncreaseAfterSellIn(sellIn: Int, quality: Int): Int;
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/quality/RegularItem.kt

@@ -0,0 +1,28 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.REGULAR
+
+
+internal class RegularItem : QualityCalculator {
+
+    override fun type(): com.platinumrose.ItemType {
+        return REGULAR
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+
+    override fun computeSellInDecrease(sellIn: Int): Int {
+        return -1
+    }
+
+    override fun computeQualityIncreaseBeforeSellIn(sellIn: Int, quality: Int): Int {
+        return -1
+    }
+
+    override fun computeQualityIncreaseAfterSellIn(sellIn: Int, quality: Int): Int {
+        return -1
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/advance/quality/Sulfuras.kt

@@ -0,0 +1,28 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.LEGENDARY_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.SULFURAS
+
+
+internal class Sulfuras : QualityCalculator {
+
+    override fun type(): com.platinumrose.ItemType {
+        return SULFURAS
+    }
+
+    override fun maxQuality(): Int {
+        return LEGENDARY_ITEM_MAX_QUALITY
+    }
+
+    override fun computeSellInDecrease(sellIn: Int): Int {
+        return 0
+    }
+
+    override fun computeQualityIncreaseBeforeSellIn(sellIn: Int, quality: Int): Int {
+        return 0
+    }
+
+    override fun computeQualityIncreaseAfterSellIn(sellIn: Int, quality: Int): Int {
+        return 0
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/mid/MidPlatinumRose.kt

@@ -0,0 +1,36 @@
+package com.platinumrose.mid
+
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.MIN_QUALITY
+import com.platinumrose.Solution
+import com.platinumrose.mid.strategy.*
+
+
+class MidPlatinumRose(var items: List<Item>) : Solution {
+    private val strategies: Map<com.platinumrose.ItemType, UpdateQualityStrategy>
+    private val defaultStrategy = DefaultStrategy()
+
+    init {
+        val agedBrieStrategy = AgedBrieStrategy()
+        val backstagePassesStrategy = BackstagePassesStrategy()
+        val sulfurasStrategy = SulfurasStrategy()
+        val strategiesList = listOf(agedBrieStrategy, backstagePassesStrategy, sulfurasStrategy)
+        strategies = strategiesList.associateBy { it.type() }
+    }
+
+    override fun items(): List<Item> {
+        return items
+    }
+
+    override fun updateQuality() {
+        for (item in items) {
+            val strategy = findUpdateQualityStrategy(item)
+            strategy.updateQuality(item)
+            item.quality = item.quality.coerceIn(MIN_QUALITY, strategy.maxQuality())
+        }
+    }
+
+    private fun findUpdateQualityStrategy(item: Item): UpdateQualityStrategy {
+        return strategies.getOrDefault(com.platinumrose.ItemType.fromValue(item.name), defaultStrategy)
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/mid/strategy/AgedBrieStrategy.kt

@@ -0,0 +1,25 @@
+package com.platinumrose.mid.strategy
+
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.AGED_BRIE
+
+
+internal class AgedBrieStrategy : UpdateQualityStrategy {
+
+    override fun type(): com.platinumrose.ItemType {
+        return AGED_BRIE
+    }
+
+    override fun updateQuality(item: Item) {
+        item.quality += 1
+        item.sellIn -= 1
+        if (item.sellIn < 0) {
+            item.quality += 1
+        }
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/mid/strategy/BackstagePassesStrategy.kt

@@ -0,0 +1,31 @@
+package com.platinumrose.mid.strategy
+
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.BACKSTAGE_PASSES
+
+
+internal class BackstagePassesStrategy : UpdateQualityStrategy {
+
+    override fun type(): com.platinumrose.ItemType {
+        return BACKSTAGE_PASSES
+    }
+
+    override fun updateQuality(item: Item) {
+        item.quality += 1
+        if (item.sellIn < 11) {
+            item.quality += 1
+        }
+        if (item.sellIn < 6) {
+            item.quality += 1
+        }
+        item.sellIn -= 1
+        if (item.sellIn < 0) {
+            item.quality = 0
+        }
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/mid/strategy/DefaultStrategy.kt

@@ -0,0 +1,25 @@
+package com.platinumrose.mid.strategy
+
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.REGULAR
+
+
+internal class DefaultStrategy : UpdateQualityStrategy {
+
+    override fun type(): com.platinumrose.ItemType {
+        return REGULAR
+    }
+
+    override fun updateQuality(item: Item) {
+        item.quality -= 1
+        item.sellIn -= 1
+        if (item.sellIn < 0) {
+            item.quality -= 1
+        }
+    }
+
+    override fun maxQuality(): Int {
+        return REGULAR_ITEM_MAX_QUALITY
+    }
+}

Kotlin/src/main/kotlin/com/platinumrose/mid/strategy/SulfurasStrategy.kt

@@ -0,0 +1,23 @@
+package com.platinumrose.mid.strategy
+
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.LEGENDARY_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.SULFURAS
+
+
+internal class SulfurasStrategy : UpdateQualityStrategy {
+
+    override fun type(): com.platinumrose.ItemType {
+        return SULFURAS
+    }
+
+    override fun updateQuality(item: Item) {
+        // nothing to do here
+    }
+
+    override fun maxQuality(): Int {
+        return LEGENDARY_ITEM_MAX_QUALITY
+    }
+}
+
+

Kotlin/src/main/kotlin/com/platinumrose/mid/strategy/UpdateQualityStrategy.kt

@@ -0,0 +1,9 @@
+package com.platinumrose.mid.strategy
+
+import com.gildedrose.Item
+
+interface UpdateQualityStrategy {
+    fun type(): com.platinumrose.ItemType
+    fun updateQuality(item: Item)
+    fun maxQuality(): Int
+}

Kotlin/src/main/kotlin/com/platinumrose/simple/SimplePlatinumRose.kt

@@ -1,6 +1,9 @@
-package com.gildedrose
+package com.platinumrose.simple
 
-class PlatinumRose(var items: List<Item>) {
+import com.gildedrose.Item
+import com.platinumrose.Solution
+
+class SimplePlatinumRose(var items: List<Item>) : Solution {
 
     companion object {
         const val MIN_QUALITY = 0
@@ -12,15 +15,20 @@ class PlatinumRose(var items: List<Item>) {
         const val LULFURAS_HAND_OF_RAGNAROK = "Sulfuras, Hand of Ragnaros"
     }
 
-    fun updateQuality() {
+
+    override fun items(): List<Item> {
+        return items
+    }
+
+
+    override fun updateQuality() {
         for (item in items) {
             when (item.name) {
-                AGED_BRIE -> updateQualityForAgedBrie(item)
+                com.platinumrose.ItemType.AGED_BRIE.value -> updateQualityForAgedBrie(item)
-                BACKSTAGE_PASSES -> updateQualityForBackstagePasses(item)
+                com.platinumrose.ItemType.BACKSTAGE_PASSES.value -> updateQualityForBackstagePasses(item)
-                LULFURAS_HAND_OF_RAGNAROK -> null
+                com.platinumrose.ItemType.SULFURAS.value -> updateQualityForSulfuras(item)
                 else -> updateQuality(item)
             }
-            item.quality = item.quality.coerceIn(0, REGULAR_ITEM_MAX_QUALITY)
         }
     }
 
@@ -30,6 +38,7 @@ class PlatinumRose(var items: List<Item>) {
         if (item.sellIn < 0) {
             item.quality -= 1
         }
+        item.quality = item.quality.coerceIn(0, REGULAR_ITEM_MAX_QUALITY)
     }
 
     private fun updateQualityForAgedBrie(item: Item) {
@@ -38,6 +47,7 @@ class PlatinumRose(var items: List<Item>) {
         if (item.sellIn < 0) {
             item.quality += 1
         }
+        item.quality = item.quality.coerceIn(0, REGULAR_ITEM_MAX_QUALITY)
     }
 
     private fun updateQualityForBackstagePasses(item: Item) {
@@ -52,5 +62,10 @@ class PlatinumRose(var items: List<Item>) {
         if (item.sellIn < 0) {
             item.quality = 0
         }
+        item.quality = item.quality.coerceIn(0, REGULAR_ITEM_MAX_QUALITY)
+    }
+
+    private fun updateQualityForSulfuras(item: Item) {
+        item.quality = item.quality.coerceIn(0, LEGENDARY_ITEM_MAX_QUALITY)
     }
 }

Kotlin/src/test/kotlin/com/gildedrose/PlatinumRoseTest.kt

@@ -1,53 +0,0 @@
-package com.gildedrose
-
-import com.gildedrose.PlatinumRose.Companion.AGED_BRIE
-import com.gildedrose.PlatinumRose.Companion.BACKSTAGE_PASSES
-import com.gildedrose.PlatinumRose.Companion.LULFURAS_HAND_OF_RAGNAROK
-import com.gildedrose.PlatinumRose.Companion.MIN_QUALITY
-import com.gildedrose.PlatinumRose.Companion.REGULAR_ITEM_MAX_QUALITY
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import java.util.*
-
-class PlatinumRoseTest {
-
-    @Test
-    fun `should update quality for generated test cases and compare with GlidedRose`() {
-        val names = listOf(
-            AGED_BRIE,
-            BACKSTAGE_PASSES,
-            LULFURAS_HAND_OF_RAGNAROK,
-            "new none-existing on code name"
-        )
-        val sellInRange = -100..100
-        val qualityRange = MIN_QUALITY..REGULAR_ITEM_MAX_QUALITY
-        val allTestCases = generateTestCasesInRanger(names, sellInRange, qualityRange)
-
-
-        for (testCase in allTestCases) {
-            val platinumRose = PlatinumRose(listOf(Item(testCase.name, testCase.sellIn, testCase.quality)))
-            val gildedRose = GildedRose(listOf(Item(testCase.name, testCase.sellIn, testCase.quality)))
-
-            platinumRose.updateQuality()
-            gildedRose.updateQuality()
-
-            assertEquals(gildedRose.items, platinumRose.items)
-        }
-    }
-
-    private fun generateTestCasesInRanger(
-        names: List<String>,
-        sellInRange: IntRange,
-        qualityRange: IntRange
-    ): List<Item> {
-        val items = LinkedList<Item>()
-        for (name in names) {
-            for (sellIn in sellInRange) {
-                for (quality in qualityRange) {
-                    items.add(Item(name, sellIn, quality))
-                }
-            }
-        }
-        return items
-    }
-}

Kotlin/src/test/kotlin/com/platinumrose/PlatinumRoseTestTemplate.kt

@@ -0,0 +1,46 @@
+package com.platinumrose
+
+import com.gildedrose.GildedRose
+import com.gildedrose.Item
+import com.platinumrose.ItemConstant.Companion.MIN_QUALITY
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import org.junit.jupiter.api.Assertions.assertEquals
+import java.util.*
+
+abstract class PlatinumRoseTestTemplate {
+    private val ITEMS_NAMES = listOf(
+        com.platinumrose.ItemType.AGED_BRIE.value!!,
+        com.platinumrose.ItemType.BACKSTAGE_PASSES.value!!,
+        com.platinumrose.ItemType.SULFURAS.value!!,
+        "new none-existing on code name"
+    )
+    private val SELLIN_RANGE = -100..100
+    private val QUALITY_RANGE = MIN_QUALITY..REGULAR_ITEM_MAX_QUALITY
+
+
+    fun generateTestCases(): List<Item> {
+        return generateTestCasesInRanger(ITEMS_NAMES, SELLIN_RANGE, QUALITY_RANGE)
+    }
+
+    fun updateQualityAndCheckResult(gildedRose: GildedRose, simplePlatinumRose: Solution) {
+        simplePlatinumRose.updateQuality()
+        gildedRose.updateQuality()
+        assertEquals(gildedRose.items, simplePlatinumRose.items())
+    }
+
+    private fun generateTestCasesInRanger(
+        names: List<String>,
+        sellInRange: IntRange,
+        qualityRange: IntRange
+    ): List<Item> {
+        val items = LinkedList<Item>()
+        for (name in names) {
+            for (sellIn in sellInRange) {
+                for (quality in qualityRange) {
+                    items.add(Item(name, sellIn, quality))
+                }
+            }
+        }
+        return items
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/AdvancePlatinumRoseTest.kt

@@ -0,0 +1,17 @@
+package com.platinumrose.advance
+
+import com.gildedrose.GildedRose
+import com.gildedrose.Item
+import com.platinumrose.PlatinumRoseTestTemplate
+import org.junit.jupiter.api.Test
+
+class AdvancePlatinumRoseTest : PlatinumRoseTestTemplate() {
+
+    @Test
+    fun `should update quality for generated test cases and compare with GlidedRose`() {
+        val allTestCases = generateTestCases()
+        val gildedRose = GildedRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        val simplePlatinumRose = AdvancePlatinumRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        updateQualityAndCheckResult(gildedRose, simplePlatinumRose)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/factory/QualityCalculatorFactoryImplTest.kt

@@ -0,0 +1,38 @@
+package com.platinumrose.advance.factory
+
+import com.platinumrose.ItemType
+import com.platinumrose.advance.quality.AgedBrie
+import com.platinumrose.advance.quality.BackstagePasses
+import com.platinumrose.advance.quality.RegularItem
+import com.platinumrose.advance.quality.Sulfuras
+import org.junit.jupiter.api.Assertions.assertInstanceOf
+import org.junit.jupiter.api.Test
+
+class QualityCalculatorFactoryImplTest {
+
+    private val qualityCalculatorFactory = QualityCalculatorFactoryImpl()
+
+    @Test
+    fun `should return expected calculator for AGED_BRIE`() {
+        val qualityCalculator = qualityCalculatorFactory.qualityCalculator(ItemType.AGED_BRIE)
+        assertInstanceOf(AgedBrie::class.java, qualityCalculator)
+    }
+
+    @Test
+    fun `should return expected calculator for BACKSTAGE_PASSES`() {
+        val qualityCalculator = qualityCalculatorFactory.qualityCalculator(ItemType.BACKSTAGE_PASSES)
+        assertInstanceOf(BackstagePasses::class.java, qualityCalculator)
+    }
+
+    @Test
+    fun `should return expected calculator for SULFURAS`() {
+        val qualityCalculator = qualityCalculatorFactory.qualityCalculator(ItemType.SULFURAS)
+        assertInstanceOf(Sulfuras::class.java, qualityCalculator)
+    }
+
+    @Test
+    fun `should return expected calculator for any other`() {
+        val qualityCalculator = qualityCalculatorFactory.qualityCalculator(ItemType.REGULAR)
+        assertInstanceOf(RegularItem::class.java, qualityCalculator)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/quality/AgedBrieTest.kt

@@ -0,0 +1,38 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import kotlin.random.Random
+
+class AgedBrieTest {
+
+    private val Random = Random(Int.MAX_VALUE)
+    private val item = AgedBrie()
+
+    @Test
+    fun `should return expected type`() {
+        assertEquals(item.type(), ItemType.AGED_BRIE)
+    }
+
+    @Test
+    fun `should return expected max quality`() {
+        assertEquals(item.maxQuality(), REGULAR_ITEM_MAX_QUALITY)
+    }
+
+    @Test
+    fun `should return -1 when calculate sell in decrease`() {
+        assertEquals(item.computeSellInDecrease(Random.nextInt()), -1)
+    }
+
+    @Test
+    fun `should return 1 when calculate quality increase before sell in`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(Random.nextInt(), Random.nextInt()), 1)
+    }
+
+    @Test
+    fun `should return 1 when calculate quality increase after sell in`() {
+        assertEquals(item.computeQualityIncreaseAfterSellIn(Random.nextInt(), Random.nextInt()), 1)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/quality/BackstagePassesTest.kt

@@ -0,0 +1,51 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant.Companion.REGULAR_ITEM_MAX_QUALITY
+import com.platinumrose.ItemType.BACKSTAGE_PASSES
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import kotlin.random.Random
+
+class BackstagePassesTest {
+
+    private val Random = Random(0)
+    private val item = BackstagePasses()
+
+    @Test
+    fun `should return expected type`() {
+        assertEquals(item.type(), BACKSTAGE_PASSES)
+    }
+
+    @Test
+    fun `should return expected max quality`() {
+        assertEquals(item.maxQuality(), REGULAR_ITEM_MAX_QUALITY)
+    }
+
+    @Test
+    fun `should return -1 when calculate sell in decrease`() {
+        assertEquals(item.computeSellInDecrease(Random.nextInt()), -1)
+    }
+
+    @Test
+    fun `should return 1 when calculate quality increase before sell in and quality greater than 10`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(Random.nextInt(12, Int.MAX_VALUE), Random.nextInt()), 1)
+    }
+
+    @Test
+    fun `should return 2 when calculate quality increase before sell in and quality between 6 and 10`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(6, Random.nextInt()), 2)
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(10, Random.nextInt()), 2)
+    }
+
+    @Test
+    fun `should return 3 when calculate quality increase before sell in and quality between 0 and 5`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(0, Random.nextInt()), 3)
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(5, Random.nextInt()), 3)
+    }
+
+    @Test
+    fun `should return negative quality when calculate quality increase after sell in`() {
+        val quality = Random.nextInt()
+        assertEquals(item.computeQualityIncreaseAfterSellIn(Random.nextInt(), quality), -quality)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/quality/RegularItemTest.kt

@@ -0,0 +1,38 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant
+import com.platinumrose.ItemType
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import kotlin.random.Random
+
+class RegularItemTest {
+
+    private val Random = Random(Int.MAX_VALUE)
+    private val item = RegularItem()
+
+    @Test
+    fun `should return expected type`() {
+        assertEquals(item.type(), ItemType.REGULAR)
+    }
+
+    @Test
+    fun `should return expected max quality`() {
+        assertEquals(item.maxQuality(), ItemConstant.REGULAR_ITEM_MAX_QUALITY)
+    }
+
+    @Test
+    fun `should return -1 when calculate sell in decrease`() {
+        assertEquals(item.computeSellInDecrease(Random.nextInt()), -1)
+    }
+
+    @Test
+    fun `should return -1 when calculate quality increase before sell in`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(Random.nextInt(), Random.nextInt()), -1)
+    }
+
+    @Test
+    fun `should return -1 when calculate quality increase after sell in`() {
+        assertEquals(item.computeQualityIncreaseAfterSellIn(Random.nextInt(), Random.nextInt()), -1)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/advance/quality/SulfurasTest.kt

@@ -0,0 +1,38 @@
+package com.platinumrose.advance.quality
+
+import com.platinumrose.ItemConstant
+import com.platinumrose.ItemType
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import kotlin.random.Random
+
+class SulfurasTest {
+
+    private val Random = Random(Int.MAX_VALUE)
+    private val item = Sulfuras()
+
+    @Test
+    fun `should return expected type`() {
+        assertEquals(item.type(), ItemType.SULFURAS)
+    }
+
+    @Test
+    fun `should return expected max quality`() {
+        assertEquals(item.maxQuality(), ItemConstant.LEGENDARY_ITEM_MAX_QUALITY)
+    }
+
+    @Test
+    fun `should return 0 when calculate sell in decrease`() {
+        assertEquals(item.computeSellInDecrease(Random.nextInt()), 0)
+    }
+
+    @Test
+    fun `should return 0 when calculate quality increase before sell in`() {
+        assertEquals(item.computeQualityIncreaseBeforeSellIn(Random.nextInt(), Random.nextInt()), 0)
+    }
+
+    @Test
+    fun `should return 0 when calculate quality increase after sell in`() {
+        assertEquals(item.computeQualityIncreaseAfterSellIn(Random.nextInt(), Random.nextInt()), 0)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/mid/MidPlatinumRoseTest.kt

@@ -0,0 +1,18 @@
+package com.platinumrose.mid
+
+import com.gildedrose.GildedRose
+import com.gildedrose.Item
+import com.platinumrose.PlatinumRoseTestTemplate
+import org.junit.jupiter.api.Test
+
+
+class MidPlatinumRoseTest : PlatinumRoseTestTemplate() {
+
+    @Test
+    fun `should update quality for generated test cases and compare with GlidedRose`() {
+        val allTestCases = generateTestCases()
+        val gildedRose = GildedRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        val solution = MidPlatinumRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        updateQualityAndCheckResult(gildedRose, solution)
+    }
+}

Kotlin/src/test/kotlin/com/platinumrose/simple/SimplePlatinumRoseTest.kt

@@ -0,0 +1,17 @@
+package com.platinumrose.simple
+
+import com.gildedrose.GildedRose
+import com.gildedrose.Item
+import com.platinumrose.PlatinumRoseTestTemplate
+import org.junit.jupiter.api.Test
+
+class SimplePlatinumRoseTest : PlatinumRoseTestTemplate() {
+
+    @Test
+    fun `should update quality for generated test cases and compare with GlidedRose`() {
+        val allTestCases = generateTestCases()
+        val gildedRose = GildedRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        val solution = SimplePlatinumRose(allTestCases.map { Item(it.name, it.sellIn, it.quality) })
+        updateQualityAndCheckResult(gildedRose, solution)
+    }
+}