Fix data contract serialization for System.Type

src/Adapter/MSTestAdapter.PlatformServices/Helpers/DataSerializationHelper.cs

@@ -21,7 +21,7 @@ internal static class DataSerializationHelper
 #if NETFRAMEWORK
         DataContractSurrogate = SerializationSurrogateProvider.Instance,
 #endif
-        KnownTypes = [typeof(SurrogatedDateOnly), typeof(SurrogatedTimeOnly)],
+        KnownTypes = [typeof(SurrogatedDateOnly), typeof(SurrogatedTimeOnly), typeof(SurrogatedSystemType)],
     };
 
     /// <summary>
@@ -50,7 +50,22 @@ internal static class DataSerializationHelper
                 continue;
             }
 
-            Type type = data[i]!.GetType();
+            object valueToSerialize = data[i]!;
+            Type type = valueToSerialize.GetType();
+
+            if (valueToSerialize is Type serializableType)
+            {
+                string assemblyQualifiedName = serializableType.AssemblyQualifiedName
+                    ?? throw new SerializationException($"Cannot serialize '{serializableType}' because it does not have an assembly-qualified name.");
+
+                valueToSerialize = new SurrogatedSystemType
+                {
+                    AssemblyQualifiedName = assemblyQualifiedName,
+                };
+
+                type = typeof(SurrogatedSystemType);
+            }
+
             string? typeName = type.AssemblyQualifiedName;
 
             serializedData[typeIndex] = typeName;
@@ -66,7 +81,7 @@ internal static class DataSerializationHelper
             // Not the best solution, maybe we can replace this with System.Text.Json, but the we need one generator calling the other.
 #pragma warning disable IL3050 // IL3050: Avoid calling members annotated with 'RequiresDynamicCodeAttribute' when publishing as Native AOT
 #pragma warning disable IL2026 // IL2026: Members attributed with RequiresUnreferencedCode may break when trimming
-            serializer.WriteObject(memoryStream, data[i]);
+            serializer.WriteObject(memoryStream, valueToSerialize);
 #pragma warning restore IL3050 // IL3050: Avoid calling members annotated with 'RequiresDynamicCodeAttribute' when publishing as Native AOT
 #pragma warning restore IL2026 // IL2026: Members attributed with RequiresUnreferencedCode may break when trimming
             byte[] serializerData = memoryStream.ToArray();
@@ -135,7 +150,7 @@ private static DataContractJsonSerializer GetSerializer(string assemblyQualified
             // Not the best solution, maybe we can replace this with System.Text.Json, but the we need one generator calling the other.
 #pragma warning disable IL3050 // IL3050: Avoid calling members annotated with 'RequiresDynamicCodeAttribute' when publishing as Native AOT
 #pragma warning disable IL2026 // IL2026: Members attributed with RequiresUnreferencedCode may break when trimming
-            _ => new DataContractJsonSerializer(PlatformServiceProvider.Instance.ReflectionOperations.GetType(assemblyQualifiedName) ?? typeof(object), SerializerSettings));
+            _ => new DataContractJsonSerializer(GetSerializationType(assemblyQualifiedName), SerializerSettings));
 #pragma warning restore IL3050 // IL3050: Avoid calling members annotated with 'RequiresDynamicCodeAttribute' when publishing as Native AOT
 #pragma warning restore IL2026 // IL2026: Members attributed with RequiresUnreferencedCode may break when trimming
 
@@ -149,6 +164,19 @@ private static DataContractJsonSerializer GetSerializer(Type type)
 #pragma warning disable IL2026 // IL2026: Members attributed with RequiresUnreferencedCode may break when trimming
             _ => new DataContractJsonSerializer(type, SerializerSettings));
 
+    private static Type GetSerializationType(string assemblyQualifiedName)
+    {
+        Type? serializedType = PlatformServiceProvider.Instance.ReflectionOperations.GetType(assemblyQualifiedName);
+        return serializedType
+            ?? (assemblyQualifiedName.StartsWith(typeof(SurrogatedSystemType).FullName + ",", StringComparison.Ordinal)
+                ? typeof(SurrogatedSystemType)
+                : assemblyQualifiedName.StartsWith(typeof(SurrogatedDateOnly).FullName + ",", StringComparison.Ordinal)
+                    ? typeof(SurrogatedDateOnly)
+                    : assemblyQualifiedName.StartsWith(typeof(SurrogatedTimeOnly).FullName + ",", StringComparison.Ordinal)
+                        ? typeof(SurrogatedTimeOnly)
+                        : typeof(object));
+    }
+
     [DataContract]
     private sealed class SurrogatedDateOnly
     {
@@ -163,6 +191,13 @@ private sealed class SurrogatedTimeOnly
         public long Ticks { get; set; }
     }
 
+    [DataContract]
+    private sealed class SurrogatedSystemType
+    {
+        [DataMember]
+        public string AssemblyQualifiedName { get; set; } = null!;
+    }
+
     private sealed class SerializationSurrogateProvider
 #if NETFRAMEWORK
         : IDataContractSurrogate
@@ -201,8 +236,10 @@ internal static object GetDeserializedObject(object obj)
                 return new TimeOnly(surrogatedTimeOnly.Ticks);
             }
 #endif
-
-            return obj;
+            return obj is SurrogatedSystemType surrogatedSystemType
+                ? PlatformServiceProvider.Instance.ReflectionOperations.GetType(surrogatedSystemType.AssemblyQualifiedName)
+                    ?? throw new SerializationException($"Cannot deserialize type '{surrogatedSystemType.AssemblyQualifiedName}'.")
+                : obj;
         }
 
         public object GetObjectToSerialize(object obj, Type targetType)

test/IntegrationTests/MSTest.IntegrationTests/Parameterized tests/DataRowTests.cs

@@ -167,7 +167,9 @@ public async Task DataRowsShouldHandleNonSerializableValues()
         // Assert
         VerifyE2E.TestsDiscovered(
             testCases,
-            "DataRowNonSerializable");
+            "DataRowNonSerializable (System.String)",
+            "DataRowNonSerializable (System.Int32)",
+            "DataRowNonSerializable (DataRowTestProject.DataRowTests_DerivedClass)");
 
         VerifyE2E.TestsPassed(
             testResults,

test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/Helpers/DataSerializationHelperTests.cs

@@ -81,4 +81,33 @@ public void DataSerializerShouldRoundTripTimeOnly()
         actual[0]!.Equals(source).Should().BeTrue();
     }
 #endif
+
+    public void DataSerializerShouldRoundTripSystemType()
+    {
+        Type[] source = [typeof(Console), typeof(DataSerializationHelperTests), typeof(DataSerializationHelper)];
+
+        foreach (Type type in source)
+        {
+            object?[]? actual = DataSerializationHelper.Deserialize(DataSerializationHelper.Serialize([type]));
+
+            actual!.Length.Should().Be(1);
+            actual[0].Should().BeAssignableTo<Type>();
+            ((Type)actual[0]!).Should().Be(type);
+        }
+    }
+
+    public void DataSerializerShouldRoundTripMixedPayloadIncludingSystemType()
+    {
+        object?[] source = [typeof(string), 42, "hello", null, new DateTime(638450000000000000)];
+
+        object?[]? actual = DataSerializationHelper.Deserialize(DataSerializationHelper.Serialize(source));
+
+        actual.Should().NotBeNull();
+        actual!.Length.Should().Be(source.Length);
+        actual[0].Should().Be(typeof(string));
+        actual[1].Should().Be(42);
+        actual[2].Should().Be("hello");
+        actual[3].Should().BeNull();
+        actual[4].Should().Be(source[4]);
+    }
 }