Merge 2477b53170 into 3e0085bfd0

csharp.xUnit/GildedRose/AgedBrieUpdater.cs

@@ -0,0 +1,16 @@
+namespace GildedRoseKata;
+
+public class AgedBrieUpdater : ItemUpdaterBase
+{
+    public override string Name => "Aged Brie";
+
+    public override void Update(Item item)
+    {
+        item.Quality = ClampQuality(item.Quality + 1);
+        item.SellIn -= 1;
+        if (item.SellIn < 0)
+        {
+            item.Quality = ClampQuality(item.Quality + 1);
+        }
+    }
+}

csharp.xUnit/GildedRose/BackstagePassUpdater.cs

@@ -0,0 +1,17 @@
+namespace GildedRoseKata;
+
+public class BackstagePassUpdater : ItemUpdaterBase
+{
+    public override string Name => "Backstage passes to a TAFKAL80ETC concert";
+
+    public override void Update(Item item)
+    {
+        var increase = item.SellIn <= 5 ? 3 : item.SellIn <= 10 ? 2 : 1;
+        item.Quality = ClampQuality(item.Quality + increase);
+        item.SellIn -= 1;
+        if (item.SellIn < 0)
+        {
+            item.Quality = 0;
+        }
+    }
+}

csharp.xUnit/GildedRose/ConjuredItemUpdater.cs

@@ -0,0 +1,17 @@
+namespace GildedRoseKata;
+
+public class ConjuredItemUpdater : ItemUpdaterBase
+{
+    // Matched by prefix in ItemUpdaterFactory: handles every "Conjured..." item.
+    public override string Name => ItemUpdaterFactory.ConjuredPrefix;
+
+    public override void Update(Item item)
+    {
+        item.Quality = ClampQuality(item.Quality - 2);
+        item.SellIn -= 1;
+        if (item.SellIn < 0)
+        {
+            item.Quality = ClampQuality(item.Quality - 2);
+        }
+    }
+}

csharp.xUnit/GildedRose/GildedRose.cs

@@ -1,89 +1,25 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 
 namespace GildedRoseKata;
 
 public class GildedRose
 {
-    IList<Item> Items;
+    private readonly IList<Item> _items;
+    private readonly IItemUpdaterFactory _factory;
 
-    public GildedRose(IList<Item> Items)
+    public GildedRose(IList<Item> items) : this(items, ItemUpdaterFactory.Default())
     {
-        this.Items = Items;
+    }
+
+    public GildedRose(IList<Item> items, IItemUpdaterFactory factory)
+    {
+        _items = items;
+        _factory = factory;
     }
 
     public void UpdateQuality()
     {
-        for (var i = 0; i < Items.Count; i++)
-        {
-            if (Items[i].Name != "Aged Brie" && Items[i].Name != "Backstage passes to a TAFKAL80ETC concert")
-            {
-                if (Items[i].Quality > 0)
-                {
-                    if (Items[i].Name != "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 == "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 != "Sulfuras, Hand of Ragnaros")
-            {
-                Items[i].SellIn = Items[i].SellIn - 1;
-            }
-
-            if (Items[i].SellIn < 0)
-            {
-                if (Items[i].Name != "Aged Brie")
-                {
-                    if (Items[i].Name != "Backstage passes to a TAFKAL80ETC concert")
-                    {
-                        if (Items[i].Quality > 0)
-                        {
-                            if (Items[i].Name != "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;
-                    }
-                }
-            }
-        }
+        foreach (var item in _items)
+            _factory.Get(item).Update(item);
     }
-}
+}

csharp.xUnit/GildedRose/IItemUpdater.cs

@@ -0,0 +1,10 @@
+namespace GildedRoseKata;
+
+public interface IItemUpdater
+{
+    /// <summary>The exact item name this strategy handles ("default" for the fallback).</summary>
+    string Name { get; }
+
+    /// <summary>Applies one full day: quality change + SellIn change + clamping.</summary>
+    void Update(Item item);
+}

csharp.xUnit/GildedRose/IItemUpdaterFactory.cs

@@ -0,0 +1,6 @@
+namespace GildedRoseKata;
+
+public interface IItemUpdaterFactory
+{
+    IItemUpdater Get(Item item);
+}

csharp.xUnit/GildedRose/ItemUpdaterBase.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace GildedRoseKata;
+
+public abstract class ItemUpdaterBase : IItemUpdater
+{
+    public const int MinQuality = 0;
+    public const int MaxQuality = 50;
+
+    public abstract string Name { get; }
+
+    public abstract void Update(Item item);
+
+    protected static int ClampQuality(int quality) => Math.Clamp(quality, MinQuality, MaxQuality);
+}

csharp.xUnit/GildedRose/ItemUpdaterFactory.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+
+namespace GildedRoseKata;
+
+public class ItemUpdaterFactory : IItemUpdaterFactory
+{
+    public const string ConjuredPrefix = "Conjured";
+    private const string DefaultName = "default";
+
+    private readonly Dictionary<string, IItemUpdater> _updatersByName;
+    private readonly IItemUpdater _fallback;
+
+    public ItemUpdaterFactory(IEnumerable<IItemUpdater> updaters)
+    {
+        _updatersByName = new Dictionary<string, IItemUpdater>(StringComparer.OrdinalIgnoreCase);
+        foreach (var updater in updaters)
+        {
+            _updatersByName[updater.Name] = updater;
+        }
+
+        if (!_updatersByName.TryGetValue(DefaultName, out _fallback))
+        {
+            throw new ArgumentException($"A \"{DefaultName}\" fallback updater is required.", nameof(updaters));
+        }
+    }
+
+    public static ItemUpdaterFactory Default() => new(new IItemUpdater[]
+    {
+        new NormalItemUpdater(),
+        new AgedBrieUpdater(),
+        new SulfurasUpdater(),
+        new BackstagePassUpdater(),
+        new ConjuredItemUpdater(),
+    });
+
+    public IItemUpdater Get(Item item)
+    {
+        if (_updatersByName.TryGetValue(item.Name, out var updater))
+        {
+            return updater;
+        }
+
+        if (item.Name.StartsWith(ConjuredPrefix, StringComparison.OrdinalIgnoreCase) &&
+            _updatersByName.TryGetValue(ConjuredPrefix, out var conjured))
+        {
+            return conjured;
+        }
+
+        return _fallback;
+    }
+}

csharp.xUnit/GildedRose/NormalItemUpdater.cs

@@ -0,0 +1,16 @@
+namespace GildedRoseKata;
+
+public class NormalItemUpdater : ItemUpdaterBase
+{
+    public override string Name => "default";
+
+    public override void Update(Item item)
+    {
+        item.Quality = ClampQuality(item.Quality - 1);
+        item.SellIn -= 1;
+        if (item.SellIn < 0)
+        {
+            item.Quality = ClampQuality(item.Quality - 1);
+        }
+    }
+}

csharp.xUnit/GildedRose/SulfurasUpdater.cs

@@ -0,0 +1,11 @@
+namespace GildedRoseKata;
+
+public class SulfurasUpdater : ItemUpdaterBase
+{
+    public override string Name => "Sulfuras, Hand of Ragnaros";
+
+    public override void Update(Item item)
+    {
+        // Legendary item: Quality stays at 80 and SellIn never changes.
+    }
+}

csharp.xUnit/GildedRoseTests/ApprovalTest.Foo.verified.txt

@@ -0,0 +1,6 @@
+[
+  {
+    Name: foo,
+    SellIn: -1
+  }
+]

csharp.xUnit/GildedRoseTests/ApprovalTest.ThirtyDays.verified.txt

@@ -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

csharp.xUnit/GildedRoseTests/GildedRoseTest.cs

@@ -1,4 +1,4 @@
-using Xunit;
+using Xunit;
 using System.Collections.Generic;
 using GildedRoseKata;
 
@@ -6,12 +6,193 @@ namespace GildedRoseTests;
 
 public class GildedRoseTest
 {
-    [Fact]
-    public void foo()
+    private const string AgedBrie = "Aged Brie";
+    private const string Sulfuras = "Sulfuras, Hand of Ragnaros";
+    private const string BackstagePass = "Backstage passes to a TAFKAL80ETC concert";
+
+    private static Item UpdateOne(string name, int sellIn, int quality)
     {
-        IList<Item> Items = new List<Item> { new Item { Name = "foo", SellIn = 0, Quality = 0 } };
-        GildedRose app = new GildedRose(Items);
+        var item = new Item { Name = name, SellIn = sellIn, Quality = quality };
+        var app = new GildedRose(new List<Item> { item });
         app.UpdateQuality();
-        Assert.Equal("fixme", Items[0].Name);
+        return item;
     }
-}
+
+    [Fact]
+    public void UpdateQuality_DoesNotChangeItemName()
+    {
+        var item = UpdateOne("foo", 0, 0);
+        Assert.Equal("foo", item.Name);
+    }
+
+    // ---------- Normal items ----------
+
+    [Fact]
+    public void NormalItem_BeforeSellBy_QualityDropsByOne()
+    {
+        var item = UpdateOne("+5 Dexterity Vest", 10, 20);
+        Assert.Equal(9, item.SellIn);
+        Assert.Equal(19, item.Quality);
+    }
+
+    [Fact]
+    public void NormalItem_OnSellByDate_QualityDropsByTwo()
+    {
+        var item = UpdateOne("+5 Dexterity Vest", 0, 20);
+        Assert.Equal(-1, item.SellIn);
+        Assert.Equal(18, item.Quality);
+    }
+
+    [Fact]
+    public void NormalItem_AfterSellBy_QualityDropsByTwo()
+    {
+        var item = UpdateOne("+5 Dexterity Vest", -1, 20);
+        Assert.Equal(-2, item.SellIn);
+        Assert.Equal(18, item.Quality);
+    }
+
+    [Fact]
+    public void NormalItem_QualityNeverNegative()
+    {
+        var item = UpdateOne("+5 Dexterity Vest", 5, 0);
+        Assert.Equal(0, item.Quality);
+    }
+
+    [Fact]
+    public void NormalItem_AfterSellByWithQualityOne_QualityStopsAtZero()
+    {
+        var item = UpdateOne("+5 Dexterity Vest", 0, 1);
+        Assert.Equal(0, item.Quality);
+    }
+
+    // ---------- Aged Brie ----------
+
+    [Fact]
+    public void AgedBrie_BeforeSellBy_QualityIncreasesByOne()
+    {
+        var item = UpdateOne(AgedBrie, 2, 0);
+        Assert.Equal(1, item.SellIn);
+        Assert.Equal(1, item.Quality);
+    }
+
+    [Fact]
+    public void AgedBrie_AfterSellBy_QualityIncreasesByTwo()
+    {
+        var item = UpdateOne(AgedBrie, 0, 10);
+        Assert.Equal(-1, item.SellIn);
+        Assert.Equal(12, item.Quality);
+    }
+
+    [Fact]
+    public void AgedBrie_QualityNeverExceedsFifty()
+    {
+        var item = UpdateOne(AgedBrie, 5, 50);
+        Assert.Equal(50, item.Quality);
+    }
+
+    [Fact]
+    public void AgedBrie_AfterSellByAtFortyNine_QualityCapsAtFifty()
+    {
+        var item = UpdateOne(AgedBrie, 0, 49);
+        Assert.Equal(50, item.Quality);
+    }
+
+    // ---------- Sulfuras ----------
+
+    [Fact]
+    public void Sulfuras_AtSellInZero_NeverChanges()
+    {
+        var item = UpdateOne(Sulfuras, 0, 80);
+        Assert.Equal(0, item.SellIn);
+        Assert.Equal(80, item.Quality);
+    }
+
+    [Fact]
+    public void Sulfuras_AtSellInMinusOne_NeverChanges()
+    {
+        var item = UpdateOne(Sulfuras, -1, 80);
+        Assert.Equal(-1, item.SellIn);
+        Assert.Equal(80, item.Quality);
+    }
+
+    // ---------- Backstage passes ----------
+
+    [Fact]
+    public void BackstagePass_MoreThanTenDays_QualityIncreasesByOne()
+    {
+        var item = UpdateOne(BackstagePass, 11, 20);
+        Assert.Equal(10, item.SellIn);
+        Assert.Equal(21, item.Quality);
+    }
+
+    [Fact]
+    public void BackstagePass_TenDaysOrLess_QualityIncreasesByTwo()
+    {
+        var item = UpdateOne(BackstagePass, 10, 20);
+        Assert.Equal(9, item.SellIn);
+        Assert.Equal(22, item.Quality);
+    }
+
+    [Fact]
+    public void BackstagePass_SixDays_QualityIncreasesByTwo()
+    {
+        var item = UpdateOne(BackstagePass, 6, 20);
+        Assert.Equal(22, item.Quality);
+    }
+
+    [Fact]
+    public void BackstagePass_FiveDaysOrLess_QualityIncreasesByThree()
+    {
+        var item = UpdateOne(BackstagePass, 5, 20);
+        Assert.Equal(4, item.SellIn);
+        Assert.Equal(23, item.Quality);
+    }
+
+    [Fact]
+    public void BackstagePass_AfterConcert_QualityDropsToZero()
+    {
+        var item = UpdateOne(BackstagePass, 0, 20);
+        Assert.Equal(-1, item.SellIn);
+        Assert.Equal(0, item.Quality);
+    }
+
+    [Fact]
+    public void BackstagePass_AtFortyNineCloseToConcert_QualityCapsAtFifty()
+    {
+        var item = UpdateOne(BackstagePass, 5, 49);
+        Assert.Equal(50, item.Quality);
+    }
+
+    // ---------- Conjured items ----------
+
+    [Fact]
+    public void ConjuredItem_BeforeSellBy_QualityDropsByTwo()
+    {
+        var item = UpdateOne("Conjured Mana Cake", 3, 6);
+        Assert.Equal(2, item.SellIn);
+        Assert.Equal(4, item.Quality);
+    }
+
+    [Fact]
+    public void ConjuredItem_OnSellByDate_QualityDropsByFour()
+    {
+        var item = UpdateOne("Conjured Mana Cake", 0, 6);
+        Assert.Equal(-1, item.SellIn);
+        Assert.Equal(2, item.Quality);
+    }
+
+    [Fact]
+    public void ConjuredItem_AfterSellBy_QualityDropsByFour()
+    {
+        var item = UpdateOne("Conjured Mana Cake", -1, 6);
+        Assert.Equal(-2, item.SellIn);
+        Assert.Equal(2, item.Quality);
+    }
+
+    [Fact]
+    public void ConjuredItem_QualityNeverNegative()
+    {
+        var item = UpdateOne("Conjured Mana Cake", 0, 3);
+        Assert.Equal(0, item.Quality);
+    }
+}