diff --git a/csharpcore/GildedRoseTests/GildedRoseTest.cs b/csharpcore/GildedRoseTests/GildedRoseTest.cs
deleted file mode 100644
index d3f7e53d..00000000
--- a/csharpcore/GildedRoseTests/GildedRoseTest.cs
+++ /dev/null
@@ -1,17 +0,0 @@
-using System.Collections.Generic;
-using GildedRoseKata;
-using NUnit.Framework;
-
-namespace GildedRoseTests;
-
-public class GildedRoseTest
-{
-    [Test]
-    public void Foo()
-    {
-        var items = new List<Item> { new Item { Name = "foo", SellIn = 0, Quality = 0 } };
-        var app = new GildedRose(items);
-        app.UpdateQuality();
-        Assert.That(items[0].Name, Is.EqualTo("fixme"));
-    }
-}
\ No newline at end of file
diff --git a/csharpcore/GildedRoseTests/GildedRoseTests.csproj b/csharpcore/GildedRoseTests/GildedRoseTests.csproj
index 738dadbb..1316e3a1 100644
--- a/csharpcore/GildedRoseTests/GildedRoseTests.csproj
+++ b/csharpcore/GildedRoseTests/GildedRoseTests.csproj
@@ -7,6 +7,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="FluentAssertions" Version="6.12.0" />
         <PackageReference Include="Verify.NUnit" Version="23.1.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
         <PackageReference Include="NUnit" Version="4.0.1" />
diff --git a/csharpcore/GildedRoseTests/UpdateQualityTestFixture.cs b/csharpcore/GildedRoseTests/UpdateQualityTestFixture.cs
new file mode 100644
index 00000000..2017ac3b
--- /dev/null
+++ b/csharpcore/GildedRoseTests/UpdateQualityTestFixture.cs
@@ -0,0 +1,247 @@
+using System.Collections.Generic;
+using FluentAssertions;
+using GildedRoseKata;
+using NUnit.Framework;
+
+namespace GildedRoseTests;
+
+public class UpdateQualityTestFixture
+{
+  
+    [Test]
+    public void PlainItems_WhenNotExpired_Should_DecreaseSellInAndQualityByOne()
+    {
+        var items = new List<Item> { new() { Name = "item 1", SellIn = 2, Quality = 3 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "item 1", SellIn = 1, Quality = 2 } };
+        
+        var app = new GildedRose(items);
+        app.UpdateQuality();
+        
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    
+    [Test]
+    public void PlainItems_WhenExpired_Should_DecreaseSellInByOneAndQualityByTwo()
+    {
+        var items = new List<Item> { new() { Name = "item 1", SellIn = 0, Quality = 5 } };
+        var expectedItemsAfterDay1 = new List<Item> { new() { Name = "item 1", SellIn = -1, Quality = 3 } };
+        var expectedItemsAfterDay2 = new List<Item> { new() { Name = "item 1", SellIn = -2, Quality = 1 } };
+        
+        
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay1);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay2);
+    }
+    
+    [Test]
+    public void ItemsQuality_Should_NeverGoBelow0()
+    {
+        var items = new List<Item>
+        {
+            new() { Name = "item 1", SellIn = 0, Quality = 0 },
+            new() { Name = "item 1", SellIn = 0, Quality = 1 }
+        };
+        var expectedItemsAfterTest = new List<Item>
+        {
+            new() { Name = "item 1", SellIn = -1, Quality = 0 },
+            new() { Name = "item 1", SellIn = -1, Quality = 0 }
+        };
+        
+        
+        var app = new GildedRose(items);
+        app.UpdateQuality();
+        
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    
+    [Test]
+    public void AgedBrie_WhenNotExpired_Should_IncreaseQualityByOne()
+    {
+        var items = new List<Item> { new() { Name = "Aged Brie", SellIn = 1, Quality = 0 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Aged Brie", SellIn = 0, Quality = 1 } };
+        
+        var app = new GildedRose(items);
+        app.UpdateQuality();
+        
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    [Test]
+    public void AgedBrie_WhenExpired_Should_IncreaseQualityByTwo()
+    {
+        var items = new List<Item> { new() { Name = "Aged Brie", SellIn = 0, Quality = 1 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Aged Brie", SellIn = -1, Quality = 3 } };
+        
+        var app = new GildedRose(items);
+        app.UpdateQuality();
+        
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    
+    [Test]
+    public void ItemsQuality_Should_NeverIncreaseAbove50()
+    {
+        var items = new List<Item> { new() { Name = "Aged Brie", SellIn = 1, Quality = 49 } };
+        var expectedItemsAfterDay1 = new List<Item> { new() { Name = "Aged Brie", SellIn = 0, Quality = 50 } };
+        var expectedItemsAfterDay2 = new List<Item> { new() { Name = "Aged Brie", SellIn = -1, Quality = 50 } };
+        
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay1);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay2);
+    }
+    
+    
+    [Test]
+    public void SulfurasHandOfRagnaros_QualityAndSellIn_NeverChange()
+    {
+        var items = new List<Item> { new() { Name = "Sulfuras, Hand of Ragnaros", SellIn = 3, Quality = 3 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Sulfuras, Hand of Ragnaros", SellIn = 3, Quality = 3 } };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    [Test]
+    [Ignore("Bug in code - support only item with exact name: Sulfuras, Hand of Ragnaros")]
+    public void Sulfuras_QualityAndSellIn_NeverChange()
+    {
+        var items = new List<Item> { new() { Name = "Sulfuras", SellIn = 3, Quality = 3 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Sulfuras", SellIn = 3, Quality = 3 } };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    [Test]
+    [Ignore("not implemented yet - Legendary Items should not take quality (constant at 80)")]
+    public void Sulfuras_Quality_IsConstant80()
+    {
+        var items = new List<Item> { new() { Name = "Sulfuras", SellIn = 3 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Sulfuras", SellIn = 3, Quality = 80 } };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    
+    [Test]
+    public void BackstagePassesFullName_WhenExpiryInOver10Days_QualityIncreaseByOne()
+    {
+        var items = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 11, Quality = 4 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 20, Quality = 40 }
+        };
+        var expectedItemsAfterTest = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 10, Quality = 5 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 19, Quality = 41 }
+        };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+
+    
+    [Test]
+    public void BackstagePassesFullName_WhenExpiryIn10To6Days_QualityIncreaseByTwo()
+    {
+        var items = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 10, Quality = 4 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 6, Quality = 41 }
+        };
+        var expectedItemsAfterTest = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 9, Quality = 6 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 5, Quality = 43 }
+        };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+   
+    [Test]
+    public void BackstagePassesFullName_WhenExpiryIn5to1Days_QualityIncreaseByThree()
+    {
+        var items = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 5, Quality = 4 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 1, Quality = 41 }
+        };
+        var expectedItemsAfterTest = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 4, Quality = 7 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 0, Quality = 44 }
+        };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+    
+    [Test]
+    public void BackstagePassesFullName_MaximumQuality_Is50()
+    {
+        var items = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 15, Quality = 49 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 10, Quality = 49 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 5, Quality = 48 }
+        };
+        var expectedItemsAfterDay1 = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 14, Quality = 50 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 9, Quality = 50 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 4, Quality = 50 }
+        };
+        var expectedItemsAfterDay2 = new List<Item>
+        {
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 13, Quality = 50 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 8, Quality = 50 },
+            new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 3, Quality = 50 }
+        };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay1);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterDay2);
+    }
+    
+    [Test]
+    public void BackstagePassesFullName_WhenExpired_QualityDropsTo0()
+    {
+        var items = new List<Item> { new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = 0, Quality = 4 } };
+        var expectedItemsAfterTest = new List<Item> { new() { Name = "Backstage passes to a TAFKAL80ETC concert", SellIn = -1, Quality = 0 } };
+       
+        var app = new GildedRose(items);
+        
+        app.UpdateQuality();
+        items.Should().BeEquivalentTo(expectedItemsAfterTest);
+    }
+}
\ No newline at end of file