Upgrade s_routeParameterRegex to [GeneratedRegex] and add direct regex unit tests

- Make RouteConfigurationService partial to support [GeneratedRegex]
- Replace static readonly Regex field with [GeneratedRegex] source-generated method
- Make RouteParameterRegex() internal for testability
- Add Properties/AssemblyInfo.cs with [InternalsVisibleTo("EssentialCSharp.Web.Tests")]
- Add RouteParameterFilterTests.cs: 13 focused unit tests calling the regex method directly
  (curly-brace params, constrained params, optional params, catch-all, square brackets,
   plus static routes that must not match)

Author: BenjaminMichaelis

EssentialCSharp.Web.Tests/RouteParameterFilterTests.cs

@@ -0,0 +1,67 @@
+using EssentialCSharp.Web.Services;
+
+namespace EssentialCSharp.Web.Tests;
+
+/// <summary>
+/// Unit tests for the route parameter regex in RouteConfigurationService.
+/// Calls RouteParameterRegex() directly to verify which patterns match (and should be
+/// excluded from the sitemap) vs. which do not (and should be included).
+/// </summary>
+public class RouteParameterFilterTests
+{
+    // --- patterns that SHOULD match (route is parameterised → excluded from sitemap) ---
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesSimpleCurlyBraceParameter()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("{chapter}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesConstrainedParameter()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("{id:guid}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesOptionalParameter()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("{id?}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesParameterWithDefault()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("{action=Index}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesCatchAllParameter()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("{*catchall}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesParameterEmbeddedInPath()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("chapter/{chapter}/listing/{listing}")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesSquareBracketSegment()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("[optional]")).IsTrue();
+
+    [Test]
+    public async Task RouteParameterRegex_MatchesSquareBracketEmbeddedInPath()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("area/[optional]/page")).IsTrue();
+
+    // --- patterns that should NOT match (static route → eligible for sitemap) ---
+
+    [Test]
+    public async Task RouteParameterRegex_DoesNotMatchBareWord()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("about")).IsFalse();
+
+    [Test]
+    public async Task RouteParameterRegex_DoesNotMatchHyphenatedRoute()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("mcp-setup")).IsFalse();
+
+    [Test]
+    public async Task RouteParameterRegex_DoesNotMatchStaticMultiSegmentPath()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("identity/account/login")).IsFalse();
+
+    [Test]
+    public async Task RouteParameterRegex_DoesNotMatchApiPrefixAlone()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch("api/listing")).IsFalse();
+
+    [Test]
+    public async Task RouteParameterRegex_DoesNotMatchEmptyString()
+        => await Assert.That(RouteConfigurationService.RouteParameterRegex().IsMatch(string.Empty)).IsFalse();
+}

EssentialCSharp.Web/Properties/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("EssentialCSharp.Web.Tests")]

EssentialCSharp.Web/Services/RouteConfigurationService.cs

@@ -3,10 +3,10 @@
 
 namespace EssentialCSharp.Web.Services;
 
-public class RouteConfigurationService : IRouteConfigurationService
+public partial class RouteConfigurationService : IRouteConfigurationService
 {
-    private static readonly Regex s_routeParameterRegex =
-        new(@"\{[^}]+\}|\[[^\]]+\]", RegexOptions.Compiled);
+    [GeneratedRegex(@"\{[^}]+\}|\[[^\]]+\]")]
+    internal static partial Regex RouteParameterRegex();
 
     private readonly IActionDescriptorCollectionProvider _ActionDescriptorCollectionProvider;
     private readonly HashSet<string> _StaticRoutes;
@@ -75,7 +75,7 @@ private HashSet<string> ExtractIndexableRoutes()
     {
         return _StaticRoutes
             .Where(route => !route.StartsWith("api/", StringComparison.OrdinalIgnoreCase))
-            .Where(route => !s_routeParameterRegex.IsMatch(route))
+            .Where(route => !RouteParameterRegex().IsMatch(route))
             .Where(route => !route.Contains("identity", StringComparison.OrdinalIgnoreCase))
             .ToHashSet(StringComparer.OrdinalIgnoreCase);
     }