perf: switch typeSb to use ValueStringBuilder

Author: TimothyMakkison

TUnit.Engine/Helpers/ValueListBuilder.cs TUnit.Core/Helpers/ValueListBuilder.csTUnit.Engine/Helpers/ValueListBuilder.cs renamed to TUnit.Core/Helpers/ValueListBuilder.cs

@@ -2,7 +2,7 @@
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 
-namespace TUnit.Engine.Helpers;
+namespace TUnit.Core.Helpers;
 
 // From https://github.com/dotnet/runtime/blob/d968dc4bbdc0c26876c2cdaadf42740e891586b9/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/ValueListBuilder.cs#L8
 internal ref partial struct ValueListBuilder<T>

TUnit.Engine/Helpers/ValueStringBuilder.cs

@@ -1,7 +1,6 @@
-using System.Text;
 using TUnit.Core;
+using TUnit.Core.Helpers;
 using TUnit.Engine.Building;
-using TUnit.Engine.Helpers;
 
 namespace TUnit.Engine.Services;
 
@@ -89,44 +88,41 @@ private static void WriteTypeNameWithGenerics(ref ValueStringBuilder vsb, Type t
     {
         // Build the full type hierarchy including all containing types
         var typeHierarchy = new ValueListBuilder<string>([null, null, null, null]);
+        var typeVsb = new ValueStringBuilder(stackalloc char[128]);
         var currentType = type;
 
         while (currentType != null)
         {
             if (currentType.IsGenericType)
             {
-                var typeSb = new StringBuilder();
                 var name = currentType.Name;
 
                 var backtickIndex = name.IndexOf('`');
                 if (backtickIndex > 0)
                 {
-#if NET6_0_OR_GREATER
-                    typeSb.Append(name.AsSpan(0, backtickIndex));
-#else
-                    typeSb.Append(name.Substring(0, backtickIndex));
-#endif
+                    typeVsb.Append(name.AsSpan(0, backtickIndex));
                 }
                 else
                 {
-                    typeSb.Append(name);
+                    typeVsb.Append(name);
                 }
 
                 // Add the generic type arguments
                 var genericArgs = currentType.GetGenericArguments();
-                typeSb.Append('<');
+                typeVsb.Append('<');
                 for (var i = 0; i < genericArgs.Length; i++)
                 {
                     if (i > 0)
                     {
-                        typeSb.Append(", ");
+                        typeVsb.Append(", ");
                     }
                     // Use the full name for generic arguments to ensure uniqueness
-                    typeSb.Append(genericArgs[i].FullName ?? genericArgs[i].Name);
+                    typeVsb.Append(genericArgs[i].FullName ?? genericArgs[i].Name);
                 }
-                typeSb.Append('>');
+                typeVsb.Append('>');
 
-                typeHierarchy.Append(typeSb.ToString());
+                typeHierarchy.Append(typeVsb.AsSpan().ToString());
+                typeVsb.Length = 0;
             }
             else
             {
@@ -140,13 +136,14 @@ private static void WriteTypeNameWithGenerics(ref ValueStringBuilder vsb, Type t
         // Append all types with + separator (matching .NET Type.FullName convention for nested types)
         for (var i = typeHierarchy.Length - 1; i >= 0; i--)
         {
-            if (i > 0)
+            if (i < typeHierarchy.Length - 1)
             {
                 vsb.Append('+');
             }
             vsb.Append(typeHierarchy[i]);
         }
         typeHierarchy.Dispose();
+        typeVsb.Dispose();
     }
 
     private static void WriteTypeWithParameters(ref ValueStringBuilder vsb, ReadOnlySpan<ParameterMetadata> parameterTypes)