Ensure 'code' extension is set. Fixes #1091

Author: commonsensesoftware

src/AspNetCore/Acceptance/Asp.Versioning.Mvc.Acceptance.Tests/OData/Basic/given a versioned ODataController/when using a query string.cs

@@ -49,6 +49,7 @@ public async Task then_get_should_return_400_for_an_unspecified_version()
         // assert
         response.StatusCode.Should().Be( BadRequest );
         problem.Type.Should().Be( ProblemDetailsDefaults.Unspecified.Type );
+        problem.Extensions["code"].ToString().Should().Be( "ApiVersionUnspecified" );
     }
 
     public when_using_a_query_string( BasicFixture fixture, ITestOutputHelper console )

src/AspNetCore/WebApi/src/Asp.Versioning.Http/Routing/EndpointProblem.cs

@@ -25,7 +25,7 @@ internal static ProblemDetailsContext New( HttpContext context, ProblemDetailsIn
             },
         };
 
-        if ( string.IsNullOrEmpty( code ) )
+        if ( !string.IsNullOrEmpty( code ) )
         {
             newContext.ProblemDetails.Extensions[nameof( code )] = code;
         }

src/Common/test/Common.Acceptance.Tests/HttpContentExtensions.cs

@@ -6,20 +6,30 @@ namespace Asp.Versioning;
 using Microsoft.AspNetCore.Mvc;
 #endif
 using System.Net.Http;
+#if NETFRAMEWORK
 using System.Net.Http.Formatting;
+#else
+using System.Net.Http.Json;
+#endif
 
 internal static class HttpContentExtensions
 {
+#if NETFRAMEWORK
     private static readonly JsonMediaTypeFormatter ProblemDetailsMediaTypeFormatter = new()
     {
         SupportedMediaTypes = { new( ProblemDetailsDefaults.MediaType.Json ) },
     };
     private static readonly IEnumerable<MediaTypeFormatter> MediaTypeFormatters = new[] { ProblemDetailsMediaTypeFormatter };
+#endif
 
     public static Task<ProblemDetails> ReadAsProblemDetailsAsync(
         this HttpContent content,
         CancellationToken cancellationToken = default ) =>
+#if NETFRAMEWORK
         content.ReadAsAsync<ProblemDetails>( MediaTypeFormatters, cancellationToken );
+#else
+        content.ReadFromJsonAsync<ProblemDetails>( cancellationToken );
+#endif
 
 #pragma warning disable IDE0060 // Remove unused parameter
 #pragma warning disable IDE0079 // Remove unnecessary suppression