Validate scopes in OpenApiDocumentProvider tests and fix scope

Author: captainsafia

src/OpenApi/src/Services/OpenApiDocumentProvider.cs

@@ -25,7 +25,9 @@ internal sealed class OpenApiDocumentProvider(IServiceProvider serviceProvider)
     /// <param name="writer">A text writer associated with the document to write to.</param>
     public async Task GenerateAsync(string documentName, TextWriter writer)
     {
-        var optionsSnapshot = serviceProvider.GetRequiredService<IOptionsSnapshot<OpenApiOptions>>();
+        // Resolving IOptionsSnapshot requires a scoped service provider.
+        using var scopedService = serviceProvider.CreateScope();
+        var optionsSnapshot = scopedService.ServiceProvider.GetRequiredService<IOptionsSnapshot<OpenApiOptions>>();
         var namedOption = optionsSnapshot.Get(documentName);
         var resolvedOpenApiVersion = namedOption.OpenApiVersion;
         await GenerateAsync(documentName, writer, resolvedOpenApiVersion);

src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentProviderTests.cs

@@ -68,7 +68,7 @@ private static IServiceProvider CreateServiceProvider(string[] documentNames)
         {
             serviceCollection.AddOpenApi(documentName);
         }
-        var serviceProvider = serviceCollection.BuildServiceProvider();
+        var serviceProvider = serviceCollection.BuildServiceProvider(validateScopes: true);
         return serviceProvider;
     }
 }