Initializing HubOptions.JsonSerializationSettings to default settings

src/Microsoft.AspNetCore.SignalR.Core/HubOptions.cs

@@ -7,6 +7,6 @@ namespace Microsoft.AspNetCore.SignalR
 {
     public class HubOptions
     {
-        public JsonSerializerSettings JsonSerializerSettings { get; set; }
+        public JsonSerializerSettings JsonSerializerSettings { get; set; } = new JsonSerializerSettings();
     }
 }

test/Microsoft.AspNetCore.SignalR.Client.FunctionalTests/Hubs.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
-using Microsoft.CSharp;
 
 namespace Microsoft.AspNetCore.SignalR.Client.FunctionalTests
 {

test/Microsoft.AspNetCore.SignalR.Tests/SignalRDependencyInjectionExtensionsTests.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Xunit;
+
+namespace Microsoft.AspNetCore.SignalR.Tests
+{
+    public class SignalRDependencyInjectionExtensionsTests
+    {
+        [Fact]
+        public void JSonSerializerSettingsShouldNotBeNullInOptions()
+        {
+            var services = new ServiceCollection();
+            services.AddOptions();
+            services.AddSignalR();
+            var serviceProvider = services.BuildServiceProvider();
+            var hubOptions = serviceProvider.GetService<IOptions<HubOptions>>();
+            Assert.NotNull(hubOptions.Value.JsonSerializerSettings);
+        }
+    }
+}