Add more DefaultUnknownEnumConverter tests

StabilityMatrix.Tests/Core/DefaultUnknownEnumConverterTests.cs

@@ -1,4 +1,5 @@
-using System.Text.Json;
+using System.Runtime.Serialization;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 using StabilityMatrix.Core.Converters.Json;
 
@@ -46,6 +47,16 @@ public class DefaultUnknownEnumConverterTests
         Assert.AreEqual(expected, result);
     }
 
+    [TestMethod]
+    public void TestDeserialize_UnknownEnum_ShouldUseEnumMemberValue()
+    {
+        const string json = "\"Value 2\"";
+
+        var result = JsonSerializer.Deserialize<UnknownEnum>(json);
+
+        Assert.AreEqual(UnknownEnum.Value2, result);
+    }
+
     [TestMethod]
     public void TestSerialize_DefaultEnum_ShouldConvert()
     {
@@ -56,6 +67,26 @@ public class DefaultUnknownEnumConverterTests
         Assert.AreEqual(expected, result);
     }
 
+    [TestMethod]
+    public void TestSerialize_UnknownEnum_ShouldUseEnumMemberValue()
+    {
+        const string json = "\"Value 2\"";
+
+        var result = JsonSerializer.Deserialize<UnknownEnum>(json);
+
+        Assert.AreEqual(UnknownEnum.Value2, result);
+    }
+
+    [TestMethod]
+    public void TestSerialize_ComplexObject_ShouldUseEnumMemberValue()
+    {
+        const string expected = "{\"Key\":\"Value 2\"}";
+
+        var result = JsonSerializer.Serialize(new { Key = UnknownEnum.Value2 });
+
+        Assert.AreEqual(expected, result);
+    }
+
     private enum NormalEnum
     {
         Unknown,
@@ -68,6 +99,8 @@ public class DefaultUnknownEnumConverterTests
     {
         Unknown,
         Value1,
+
+        [EnumMember(Value = "Value 2")]
         Value2
     }