Fix issue with source generator not generating sample registry to test against

Author: michael-hawker

common/CommunityToolkit.Labs.Core.SourceGenerators/ToolkitSampleMetadataGenerator.Sample.cs

@@ -107,6 +107,7 @@ void Execute(IncrementalValuesProvider<ISymbol> types, bool skipDiagnostics = fa
                 var currentAssembly = data.Right;
 
                 var isExecutingInSampleProject = currentAssembly?.EndsWith(".Samples") ?? false;
+                var isExecutingInTestProject = currentAssembly?.EndsWith(".Tests") ?? false;
 
                 // Reconstruct sample metadata from attributes
                 var sampleMetadata = toolkitSampleAttributeData
@@ -132,7 +133,9 @@ void Execute(IncrementalValuesProvider<ISymbol> types, bool skipDiagnostics = fa
                     ReportDocumentDiagnostics(ctx, sampleMetadata, markdownFileData, toolkitSampleAttributeData, docFrontMatter);
                 }
 
-                if (!isExecutingInSampleProject && !skipRegistry)
+                // For tests we need one pass to do diagnostics and registry as we're in a contrived environment that'll have both our scenarios. Though we check if we have anything to write, as we will hit both executes.
+                if ((!isExecutingInSampleProject && !skipRegistry) ||
+                    (isExecutingInTestProject && (docFrontMatter.Any() || sampleMetadata.Any())))
                 {
                     CreateDocumentRegistry(ctx, docFrontMatter);
                     CreateSampleRegistry(ctx, sampleMetadata);