From 05aff7835db2b570ad633ab2f74c6c46d32bce0c Mon Sep 17 00:00:00 2001
From: Vladimir Pecanac <vladimir.pecanac@gmail.com>
Date: Sun, 4 Oct 2026 12:40:50 +0200
Subject: [PATCH] Custom JsonConverter: move to .NET 10 and add registration
 tests

- Retarget both projects from net7.0 to net10.0.
- Newtonsoft.Json 13.0.3 to 13.0.4.
- Test packages: Microsoft.NET.Test.Sdk 18.10.1, xunit 2.9.3,
  xunit.runner.visualstudio 4.0.0, coverlet.collector 10.1.0.
- Remove the unused Microsoft.AspNetCore.Mvc.Testing reference.
- Drop the CanWrite and CanRead overrides from SmartContactConverter;
  both repeat the base class defaults.
- Add ConverterRegistrationUnitTest: a converter registered through
  JsonSerializerSettings.Converters, and a type carrying the
  JsonConverter attribute.
---
 .../ConverterRegistrationUnitTest.cs          | 42 +++++++++++++++++++
 .../CustomJsonConverter.Tests.csproj          | 13 +++---
 .../Converters/SmartContactConverter.cs       |  4 --
 .../CustomJsonConverter.csproj                |  4 +-
 4 files changed, 50 insertions(+), 13 deletions(-)
 create mode 100644 json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/ConverterRegistrationUnitTest.cs

diff --git a/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/ConverterRegistrationUnitTest.cs b/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/ConverterRegistrationUnitTest.cs
new file mode 100644
index 0000000000..765d64e140
--- /dev/null
+++ b/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/ConverterRegistrationUnitTest.cs
@@ -0,0 +1,42 @@
+using CustomJsonConverter.Converters;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace CustomJsonConverter.Tests;
+
+[JsonConverter(typeof(ImprovedContactConverter))]
+public record class TaggedContact(string Name, Department Department, string Phone, Address Address)
+    : Contact(Name, Department, Phone, Address);
+
+public class ConverterRegistrationUnitTest
+{
+    [Fact]
+    public void GivenListOfContacts_WhenConverterIsRegisteredInSettings_ThenWritesCustomizedOutput()
+    {
+        var contacts = DataSource.GetContacts();
+        var settings = new JsonSerializerSettings
+        {
+            Converters = { new SmartContactConverter() }
+        };
+
+        var json = JsonConvert.SerializeObject(contacts, settings);
+
+        Assert.Equal(@"[{""Name"":""John"",""Department"":""Admin"",""Address"":{""Street"":""Street 1"",""City"":""City 1""}},{""Name"":""Jane"",""Department"":""CustomerCare"",""Phone"":""+2341"",""Address"":{""Street"":""Street 2"",""City"":""City 2""}},{""Name"":""Mike"",""Department"":""Operations"",""Address"":{""Street"":""Street 3"",""City"":""City 3""}}]", json);
+    }
+
+    [Fact]
+    public void GivenTypeWithConverterAttribute_WhenRoundTripped_ThenConverterWritesAndDefaultContractReads()
+    {
+        var contact = new TaggedContact("John", Department.Admin, "+1234", new("Street 1", "City 1"));
+
+        var json = JsonConvert.SerializeObject(contact);
+
+        Assert.Equal(@"{""Name"":""John"",""Department"":1}", json);
+
+        var restored = JsonConvert.DeserializeObject<TaggedContact>(json)!;
+
+        Assert.Equal("John", restored.Name);
+        Assert.Equal(Department.Admin, restored.Department);
+        Assert.Null(restored.Phone);
+    }
+}
diff --git a/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/CustomJsonConverter.Tests.csproj b/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/CustomJsonConverter.Tests.csproj
index ed22e9cd8c..7d92581b96 100644
--- a/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/CustomJsonConverter.Tests.csproj
+++ b/json-csharp/CustomJsonConverter/CustomJsonConverter.Tests/CustomJsonConverter.Tests.csproj
@@ -1,21 +1,20 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="7.0.3" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
-    <PackageReference Include="xunit" Version="2.4.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="4.0.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="3.2.0">
+    <PackageReference Include="coverlet.collector" Version="10.1.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
diff --git a/json-csharp/CustomJsonConverter/CustomJsonConverter/Converters/SmartContactConverter.cs b/json-csharp/CustomJsonConverter/CustomJsonConverter/Converters/SmartContactConverter.cs
index 8d2b9f1067..f38295fab5 100644
--- a/json-csharp/CustomJsonConverter/CustomJsonConverter/Converters/SmartContactConverter.cs
+++ b/json-csharp/CustomJsonConverter/CustomJsonConverter/Converters/SmartContactConverter.cs
@@ -41,8 +41,4 @@ public override void WriteJson(JsonWriter writer, Contact? contact, JsonSerializ
 
         return jo.ToObject<Contact>();
     }
-
-    public override bool CanWrite => true;
-
-    public override bool CanRead => true;
 }
\ No newline at end of file
diff --git a/json-csharp/CustomJsonConverter/CustomJsonConverter/CustomJsonConverter.csproj b/json-csharp/CustomJsonConverter/CustomJsonConverter/CustomJsonConverter.csproj
index 51eb283c58..ab6ddb3aff 100644
--- a/json-csharp/CustomJsonConverter/CustomJsonConverter/CustomJsonConverter.csproj
+++ b/json-csharp/CustomJsonConverter/CustomJsonConverter/CustomJsonConverter.csproj
@@ -1,13 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
   </ItemGroup>
 
 </Project>