diff --git a/Directory.Packages.props b/Directory.Packages.props
index c17bf7a6a..e10d039e0 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="AvalonEdit" Version="6.3.1.120" />
+    <PackageVersion Include="AwesomeAssertions" Version="9.4.0" />
     <PackageVersion Include="CliWrap" Version="3.10.0" />
     <PackageVersion Include="DataGridExtensions" Version="2.9.1" />
     <PackageVersion Include="DiffLib" Version="2025.0.0" />
@@ -38,7 +39,6 @@
     <PackageVersion Include="NUnit3TestAdapter" Version="6.1.0" />
     <PackageVersion Include="NuGet.Protocol" Version="7.3.0" />
     <PackageVersion Include="PowerShellStandard.Library" Version="5.1.1" />
-    <PackageVersion Include="Shouldly" Version="4.3.0" />
     <PackageVersion Include="System.Composition.AttributedModel" Version="10.0.5" />
     <PackageVersion Include="System.Collections.Immutable" Version="10.0.5" />
     <PackageVersion Include="System.Memory" Version="4.6.3" />
diff --git a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
index d5556c2ae..3392532b4 100644
--- a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -13,7 +13,7 @@
     <RuntimeIdentifier Condition="$(IsWindowsARM64) == true">win-arm64</RuntimeIdentifier>
 
     <IsPackable>false</IsPackable>
-    
+
     <GenerateTestingPlatformEntryPoint>true</GenerateTestingPlatformEntryPoint>
     <StartupObject>ICSharpCode.Decompiler.Tests.MicrosoftTestingPlatformEntryPoint</StartupObject>
     <OutputType>Exe</OutputType>
@@ -69,9 +69,9 @@
     <PackageReference Include="NUnit3TestAdapter" />
     <PackageReference Include="coverlet.MTP" />
     <PackageReference Include="NUnit" />
-    <PackageReference Include="Shouldly" />
+    <PackageReference Include="AwesomeAssertions" />
     <PackageReference Include="Microsoft.Testing.Extensions.TrxReport" />
-	<PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
+    <PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
     <PackageReference Include="System.Memory" />
     <PackageReference Include="Mono.Cecil" />
     <PackageReference Include="Microsoft.NETCore.ILAsm" />
diff --git a/ILSpy.BamlDecompiler.Tests/ILSpy.BamlDecompiler.Tests.csproj b/ILSpy.BamlDecompiler.Tests/ILSpy.BamlDecompiler.Tests.csproj
index 3fb1dc87a..59275ab45 100644
--- a/ILSpy.BamlDecompiler.Tests/ILSpy.BamlDecompiler.Tests.csproj
+++ b/ILSpy.BamlDecompiler.Tests/ILSpy.BamlDecompiler.Tests.csproj
@@ -38,9 +38,9 @@
   <ItemGroup>
     <PackageReference Include="NUnit" />
     <PackageReference Include="NUnit3TestAdapter" />
-    <PackageReference Include="Shouldly" />
+    <PackageReference Include="AwesomeAssertions" />
     <PackageReference Include="Microsoft.Testing.Extensions.TrxReport" />
-	<PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
+    <PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
     <PackageReference Include="coverlet.MTP" />
   </ItemGroup>
 
diff --git a/ILSpy.Tests/CommandLineArgumentsTests.cs b/ILSpy.Tests/CommandLineArgumentsTests.cs
index a5d23e818..efd44a8d9 100644
--- a/ILSpy.Tests/CommandLineArgumentsTests.cs
+++ b/ILSpy.Tests/CommandLineArgumentsTests.cs
@@ -1,6 +1,6 @@
 using System;
 
-using Shouldly;
+using AwesomeAssertions;
 
 using ICSharpCode.ILSpy.AppEnv;
 
@@ -16,28 +16,28 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { });
 
-			cmdLineArgs.AssembliesToLoad.ShouldBeEmpty();
-			cmdLineArgs.SingleInstance.ShouldBeNull();
-			cmdLineArgs.NavigateTo.ShouldBeNull();
-			cmdLineArgs.Search.ShouldBeNull();
-			cmdLineArgs.Language.ShouldBeNull();
-			cmdLineArgs.NoActivate.ShouldBeFalse();
-			cmdLineArgs.ConfigFile.ShouldBeNull();
+			cmdLineArgs.AssembliesToLoad.Should().BeEmpty();
+			cmdLineArgs.SingleInstance.Should().BeNull();
+			cmdLineArgs.NavigateTo.Should().BeNull();
+			cmdLineArgs.Search.Should().BeNull();
+			cmdLineArgs.Language.Should().BeNull();
+			cmdLineArgs.NoActivate.Should().BeFalse();
+			cmdLineArgs.ConfigFile.Should().BeNull();
 		}
 
 		[Test]
 		public void VerifyHelpOption()
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--help" });
-			cmdLineArgs.ArgumentsParser.IsShowingInformation.ShouldBeTrue();
+			cmdLineArgs.ArgumentsParser.IsShowingInformation.Should().BeTrue();
 		}
 
 		[Test]
 		public void VerifyForceNewInstanceOption()
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--newinstance" });
-			cmdLineArgs.SingleInstance.ShouldNotBeNull();
-			cmdLineArgs.SingleInstance.Value.ShouldBeFalse();
+			cmdLineArgs.SingleInstance.Should().NotBeNull();
+			cmdLineArgs.SingleInstance.Value.Should().BeFalse();
 		}
 
 		[Test]
@@ -45,14 +45,14 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			const string navigateTo = "MyNamespace.MyClass";
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--navigateto", navigateTo });
-			cmdLineArgs.NavigateTo.ShouldBe(navigateTo);
+			cmdLineArgs.NavigateTo.Should().Be(navigateTo);
 		}
 
 		[Test]
 		public void VerifyNavigateToOption_NoneTest_Matching_VSAddin()
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--navigateto:none" });
-			cmdLineArgs.NavigateTo.ShouldBe("none");
+			cmdLineArgs.NavigateTo.Should().Be("none");
 		}
 
 		[Test]
@@ -60,7 +60,7 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--navigateTo:none" });
 
-			cmdLineArgs.ArgumentsParser.RemainingArguments.Count.ShouldBe(1);
+			cmdLineArgs.ArgumentsParser.RemainingArguments.Count.Should().Be(1);
 		}
 
 		[Test]
@@ -68,7 +68,7 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			const string searchWord = "TestContainers";
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--search", searchWord });
-			cmdLineArgs.Search.ShouldBe(searchWord);
+			cmdLineArgs.Search.Should().Be(searchWord);
 		}
 
 		[Test]
@@ -76,7 +76,7 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			const string language = "csharp";
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--language", language });
-			cmdLineArgs.Language.ShouldBe(language);
+			cmdLineArgs.Language.Should().Be(language);
 		}
 
 		[Test]
@@ -84,21 +84,21 @@ namespace ICSharpCode.ILSpy.Tests
 		{
 			const string configFile = "myilspyoptions.xml";
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--config", configFile });
-			cmdLineArgs.ConfigFile.ShouldBe(configFile);
+			cmdLineArgs.ConfigFile.Should().Be(configFile);
 		}
 
 		[Test]
 		public void VerifyNoActivateOption()
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "--noactivate" });
-			cmdLineArgs.NoActivate.ShouldBeTrue();
+			cmdLineArgs.NoActivate.Should().BeTrue();
 		}
 
 		[Test]
 		public void MultipleAssembliesAsArguments()
 		{
 			var cmdLineArgs = CommandLineArguments.Create(new string[] { "assembly1", "assembly2", "assembly3" });
-			cmdLineArgs.AssembliesToLoad.Count.ShouldBe(3);
+			cmdLineArgs.AssembliesToLoad.Count.Should().Be(3);
 		}
 
 		[Test]
@@ -118,10 +118,10 @@ namespace ICSharpCode.ILSpy.Tests
 			{
 			}
 
-			cmdLineArgs.SingleInstance.ShouldNotBeNull();
-			cmdLineArgs.SingleInstance.Value.ShouldBeFalse();
-			cmdLineArgs.NoActivate.ShouldBeTrue();
-			cmdLineArgs.AssembliesToLoad.Count.ShouldBe(3);
+			cmdLineArgs.SingleInstance.Should().NotBeNull();
+			cmdLineArgs.SingleInstance.Value.Should().BeFalse();
+			cmdLineArgs.NoActivate.Should().BeTrue();
+			cmdLineArgs.AssembliesToLoad.Count.Should().Be(3);
 		}
 	}
 }
diff --git a/ILSpy.Tests/ILSpy.Tests.csproj b/ILSpy.Tests/ILSpy.Tests.csproj
index 773c10241..05382fc29 100644
--- a/ILSpy.Tests/ILSpy.Tests.csproj
+++ b/ILSpy.Tests/ILSpy.Tests.csproj
@@ -77,9 +77,9 @@
     <PackageReference Include="NUnit3TestAdapter" />
     <PackageReference Include="coverlet.MTP" />
     <PackageReference Include="NUnit" />
-    <PackageReference Include="Shouldly" />
+    <PackageReference Include="AwesomeAssertions" />
     <PackageReference Include="Microsoft.Testing.Extensions.TrxReport" />
-	<PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
+    <PackageReference Include="Microsoft.Testing.Extensions.VSTestBridge" />
   </ItemGroup>
 
   <ItemGroup>