From 2b4307cd3185ed0619211709242b5b9edc3a2148 Mon Sep 17 00:00:00 2001
From: Bjorn Misseghers <bjorn.misseghers@unifiedpost.com>
Date: Tue, 13 Apr 2021 11:25:58 +0200
Subject: [PATCH] Allow passing of quality decrease numbers via the constructor

We need to be able to configure other levels of decay. When passing no
parameters, the behavior remains as it was
---
 .../quality/DecreasingQualityBehavior.java    | 18 +++++--
 .../DecreasingQualityBehaviorTest.java        | 52 ++++++++++++++++++-
 2 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/Java/src/main/java/com/gildedrose/behavior/quality/DecreasingQualityBehavior.java b/Java/src/main/java/com/gildedrose/behavior/quality/DecreasingQualityBehavior.java
index 4b00258e..7c668254 100644
--- a/Java/src/main/java/com/gildedrose/behavior/quality/DecreasingQualityBehavior.java
+++ b/Java/src/main/java/com/gildedrose/behavior/quality/DecreasingQualityBehavior.java
@@ -6,11 +6,23 @@ public class DecreasingQualityBehavior implements QualityBehavior {
 
     public static final int MAX_QUALITY_LEVEL = 50;
     public static final int MIN_QUALITY_LEVEL = 0;
-    public static final int DEFAULT_QUALITY_DECREASE = 1;
+    public static final int NORMAL_QUALITY_DECREASE = 1;
     public static final int FASTER_QUALITY_DECREASE = 2;
 
+    private final int normalDecreaseSpeed;
+    private final int fasterDecreaseSpeed;
+
+    private DecreasingQualityBehavior(int normalDecreaseSpeed, int fasterDecreaseSpeed) {
+        this.normalDecreaseSpeed = normalDecreaseSpeed;
+        this.fasterDecreaseSpeed = fasterDecreaseSpeed;
+    }
+
     public static DecreasingQualityBehavior newInstance() {
-        return new DecreasingQualityBehavior();
+        return new DecreasingQualityBehavior(NORMAL_QUALITY_DECREASE, FASTER_QUALITY_DECREASE);
+    }
+
+    public static DecreasingQualityBehavior newInstance(int normalDecreaseSpeed, int fasterDecreaseSpeed) {
+        return new DecreasingQualityBehavior(normalDecreaseSpeed, fasterDecreaseSpeed);
     }
 
     @Override
@@ -23,7 +35,7 @@ public class DecreasingQualityBehavior implements QualityBehavior {
     }
 
     private int getQualityDecreaseAmount(Item item) {
-        return item.sellIn > 0 ? DEFAULT_QUALITY_DECREASE : FASTER_QUALITY_DECREASE;
+        return item.sellIn > 0 ? normalDecreaseSpeed : fasterDecreaseSpeed;
     }
     private int limitQuality(int newQuality) {
         return Math.max(MIN_QUALITY_LEVEL, Math.min(MAX_QUALITY_LEVEL, newQuality));
diff --git a/Java/src/test/java/com/gildedrose/behavior/quality/DecreasingQualityBehaviorTest.java b/Java/src/test/java/com/gildedrose/behavior/quality/DecreasingQualityBehaviorTest.java
index ff53009c..60ef973b 100644
--- a/Java/src/test/java/com/gildedrose/behavior/quality/DecreasingQualityBehaviorTest.java
+++ b/Java/src/test/java/com/gildedrose/behavior/quality/DecreasingQualityBehaviorTest.java
@@ -9,10 +9,12 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 public class DecreasingQualityBehaviorTest {
 
     private QualityBehavior qualityBehavior;
+    private QualityBehavior fastDecreasingQualityBehavior;
 
     @BeforeEach
     public void setUp() throws Exception {
-        qualityBehavior = new DecreasingQualityBehavior();
+        qualityBehavior = DecreasingQualityBehavior.newInstance();
+        fastDecreasingQualityBehavior = DecreasingQualityBehavior.newInstance(2,4);
     }
 
     @Test
@@ -63,6 +65,54 @@ public class DecreasingQualityBehaviorTest {
         assertEquals(0, item.quality);
     }
 
+    @Test
+    void fastDecreaseQuality() {
+        Item item = getItem(5,10);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(8, item.quality);
+    }
+
+    @Test
+    void fastDecreaseNegativeQuality() {
+        Item item = getItem(5,-10);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(0, item.quality);
+    }
+
+    @Test
+    void fastDecreaseQualityZero() {
+        Item item = getItem(5,0);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(0, item.quality);
+    }
+
+    @Test
+    void fastDecreaseQualityFaster() {
+        Item item = getItem(0,8);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(4, item.quality);
+    }
+
+    @Test
+    void fastDecreaseQualityFasterNegativeSellIn() {
+        Item item = getItem(-1,8);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(4, item.quality);
+    }
+
+    @Test
+    void fastDecreaseQualityFasterRespectLowerLimit() {
+        Item item = getItem(0,1);
+        fastDecreasingQualityBehavior.processQualityUpdate(item);
+
+        assertEquals(0, item.quality);
+    }
+
     private Item getItem(int sellIn, int quality) {
         return new Item("SomeItem", sellIn, quality);
     }