chore: import upstream snapshot with attribution

dotnet/tests/Microsoft.Agents.AI.DurableTask.UnitTests/State/DurableAgentStateMessageTests.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Text.Json;
+using Microsoft.Agents.AI.DurableTask.State;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.DurableTask.Tests.Unit.State;
+
+public sealed class DurableAgentStateMessageTests
+{
+    [Fact]
+    public void MessageSerializationDeserialization()
+    {
+        // Arrange
+        TextContent textContent = new("Hello, world!");
+        ChatMessage message = new(ChatRole.User, [textContent])
+        {
+            AuthorName = "User123",
+            CreatedAt = DateTimeOffset.UtcNow
+        };
+
+        DurableAgentStateMessage durableMessage = DurableAgentStateMessage.FromChatMessage(message);
+
+        // Act
+        string jsonContent = JsonSerializer.Serialize(
+            durableMessage,
+            DurableAgentStateJsonContext.Default.GetTypeInfo(typeof(DurableAgentStateMessage))!);
+
+        DurableAgentStateMessage? convertedJsonContent = (DurableAgentStateMessage?)JsonSerializer.Deserialize(
+            jsonContent,
+            DurableAgentStateJsonContext.Default.GetTypeInfo(typeof(DurableAgentStateMessage))!);
+
+        // Assert
+        Assert.NotNull(convertedJsonContent);
+
+        ChatMessage convertedMessage = convertedJsonContent.ToChatMessage();
+
+        Assert.Equal(message.AuthorName, convertedMessage.AuthorName);
+        Assert.Equal(message.CreatedAt, convertedMessage.CreatedAt);
+        Assert.Equal(message.Role, convertedMessage.Role);
+
+        AIContent convertedContent = Assert.Single(convertedMessage.Contents);
+        TextContent convertedTextContent = Assert.IsType<TextContent>(convertedContent);
+
+        Assert.Equal(textContent.Text, convertedTextContent.Text);
+    }
+}