.NET: Improve unit test coverage for Microsoft.Agents.AI.Abstractions (#3381)

* Initial plan * Add unit tests to improve coverage for Microsoft.Agents.AI.Abstractions Co-authored-by: rogerbarreto <19890735+rogerbarreto@users.noreply.github.com> * Fix file encoding and naming rule violation in new test files Co-authored-by: rogerbarreto <19890735+rogerbarreto@users.noreply.github.com> * Remove ChatMessageStoreExtensionsTests.cs to avoid duplication with Wesley's work Co-authored-by: rogerbarreto <19890735+rogerbarreto@users.noreply.github.com> * Fix AgentThread to AgentSession rename in unit tests Update MockAgentWithName in AIAgentTests.cs and DelegatingAIAgentTests.cs to use the renamed AgentSession class and corresponding methods: - AgentThread -> AgentSession - GetNewThreadAsync -> GetNewSessionAsync - DeserializeThreadAsync -> DeserializeSessionAsync - thread parameter -> session parameter * Fix: Rename GetNewSessionAsync to CreateSessionAsync to match API changes * Fix: Add SerializeSession override and remove async from DeserializeSessionAsync --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: rogerbarreto <19890735+rogerbarreto@users.noreply.github.com>
2026-06-16 21:04:09 +08:00 · 2026-02-04 17:43:31 +00:00
parent 6255abd687
commit e8902c0d11
9 changed files with 713 additions and 0 deletions
@@ -0,0 +1,42 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+namespace Microsoft.Agents.AI.Abstractions.UnitTests;
+
+/// <summary>
+/// Unit tests for the <see cref="AIAgentMetadata"/> class.
+/// </summary>
+public class AIAgentMetadataTests
+{
+    [Fact]
+    public void Constructor_WithNoArguments_SetsProviderNameToNull()
+    {
+        // Arrange & Act
+        AIAgentMetadata metadata = new();
+
+        // Assert
+        Assert.Null(metadata.ProviderName);
+    }
+
+    [Fact]
+    public void Constructor_WithProviderName_SetsProperty()
+    {
+        // Arrange
+        const string ProviderName = "TestProvider";
+
+        // Act
+        AIAgentMetadata metadata = new(ProviderName);
+
+        // Assert
+        Assert.Equal(ProviderName, metadata.ProviderName);
+    }
+
+    [Fact]
+    public void Constructor_WithNullProviderName_SetsProviderNameToNull()
+    {
+        // Arrange & Act
+        AIAgentMetadata metadata = new(null);
+
+        // Assert
+        Assert.Null(metadata.ProviderName);
+    }
+}
@@ -364,6 +364,74 @@ public class AIAgentTests

    #endregion

+    #region Name and Description Property Tests
+
+    /// <summary>
+    /// Verify that Name property returns the value from the derived class.
+    /// </summary>
+    [Fact]
+    public void Name_ReturnsValueFromDerivedClass()
+    {
+        // Arrange
+        var agent = new MockAgentWithName("TestAgentName", "TestAgentDescription");
+
+        // Act
+        string? name = agent.Name;
+
+        // Assert
+        Assert.Equal("TestAgentName", name);
+    }
+
+    /// <summary>
+    /// Verify that Description property returns the value from the derived class.
+    /// </summary>
+    [Fact]
+    public void Description_ReturnsValueFromDerivedClass()
+    {
+        // Arrange
+        var agent = new MockAgentWithName("TestAgentName", "TestAgentDescription");
+
+        // Act
+        string? description = agent.Description;
+
+        // Assert
+        Assert.Equal("TestAgentDescription", description);
+    }
+
+    /// <summary>
+    /// Verify that Name property returns null when not overridden.
+    /// </summary>
+    [Fact]
+    public void Name_ReturnsNullByDefault()
+    {
+        // Arrange
+        var agent = new MockAgent();
+
+        // Act
+        string? name = agent.Name;
+
+        // Assert
+        Assert.Null(name);
+    }
+
+    /// <summary>
+    /// Verify that Description property returns null when not overridden.
+    /// </summary>
+    [Fact]
+    public void Description_ReturnsNullByDefault()
+    {
+        // Arrange
+        var agent = new MockAgent();
+
+        // Act
+        string? description = agent.Description;
+
+        // Assert
+        Assert.Null(description);
+    }
+
+    #endregion
+
    /// <summary>
    /// Typed mock session.
    /// </summary>
@@ -402,6 +470,44 @@ public class AIAgentTests
            throw new NotImplementedException();
    }

+    private sealed class MockAgentWithName : AIAgent
+    {
+        private readonly string? _name;
+        private readonly string? _description;
+
+        public MockAgentWithName(string? name, string? description)
+        {
+            this._name = name;
+            this._description = description;
+        }
+
+        public override string? Name => this._name;
+        public override string? Description => this._description;
+
+        public override ValueTask<AgentSession> CreateSessionAsync(CancellationToken cancellationToken = default)
+            => throw new NotImplementedException();
+
+        public override ValueTask<AgentSession> DeserializeSessionAsync(JsonElement serializedSession, JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+            => throw new NotImplementedException();
+
+        public override JsonElement SerializeSession(AgentSession session, JsonSerializerOptions? jsonSerializerOptions = null)
+            => throw new NotImplementedException();
+
+        protected override Task<AgentResponse> RunCoreAsync(
+            IEnumerable<ChatMessage> messages,
+            AgentSession? session = null,
+            AgentRunOptions? options = null,
+            CancellationToken cancellationToken = default) =>
+            throw new NotImplementedException();
+
+        protected override IAsyncEnumerable<AgentResponseUpdate> RunCoreStreamingAsync(
+            IEnumerable<ChatMessage> messages,
+            AgentSession? session = null,
+            AgentRunOptions? options = null,
+            CancellationToken cancellationToken = default) =>
+            throw new NotImplementedException();
+    }
+
    private static async IAsyncEnumerable<T> ToAsyncEnumerableAsync<T>(IEnumerable<T> values)
    {
        await Task.Yield();
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.

 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Threading;
 using System.Threading.Tasks;
@@ -155,6 +156,111 @@ public class AIContextProviderTests

    #endregion

+    #region InvokingContext Tests
+
+    [Fact]
+    public void InvokingContext_RequestMessages_SetterThrowsForNull()
+    {
+        // Arrange
+        var messages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var context = new AIContextProvider.InvokingContext(messages);
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => context.RequestMessages = null!);
+    }
+
+    [Fact]
+    public void InvokingContext_RequestMessages_SetterRoundtrips()
+    {
+        // Arrange
+        var initialMessages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var newMessages = new List<ChatMessage> { new(ChatRole.User, "New message") };
+        var context = new AIContextProvider.InvokingContext(initialMessages);
+
+        // Act
+        context.RequestMessages = newMessages;
+
+        // Assert
+        Assert.Same(newMessages, context.RequestMessages);
+    }
+
+    #endregion
+
+    #region InvokedContext Tests
+
+    [Fact]
+    public void InvokedContext_RequestMessages_SetterThrowsForNull()
+    {
+        // Arrange
+        var messages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var context = new AIContextProvider.InvokedContext(messages, aiContextProviderMessages: null);
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => context.RequestMessages = null!);
+    }
+
+    [Fact]
+    public void InvokedContext_RequestMessages_SetterRoundtrips()
+    {
+        // Arrange
+        var initialMessages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var newMessages = new List<ChatMessage> { new(ChatRole.User, "New message") };
+        var context = new AIContextProvider.InvokedContext(initialMessages, aiContextProviderMessages: null);
+
+        // Act
+        context.RequestMessages = newMessages;
+
+        // Assert
+        Assert.Same(newMessages, context.RequestMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_AIContextProviderMessages_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var aiContextMessages = new List<ChatMessage> { new(ChatRole.System, "AI context message") };
+        var context = new AIContextProvider.InvokedContext(requestMessages, aiContextProviderMessages: null);
+
+        // Act
+        context.AIContextProviderMessages = aiContextMessages;
+
+        // Assert
+        Assert.Same(aiContextMessages, context.AIContextProviderMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_ResponseMessages_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var responseMessages = new List<ChatMessage> { new(ChatRole.Assistant, "Response message") };
+        var context = new AIContextProvider.InvokedContext(requestMessages, aiContextProviderMessages: null);
+
+        // Act
+        context.ResponseMessages = responseMessages;
+
+        // Assert
+        Assert.Same(responseMessages, context.ResponseMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_InvokeException_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new ReadOnlyCollection<ChatMessage>([new(ChatRole.User, "Hello")]);
+        var exception = new InvalidOperationException("Test exception");
+        var context = new AIContextProvider.InvokedContext(requestMessages, aiContextProviderMessages: null);
+
+        // Act
+        context.InvokeException = exception;
+
+        // Assert
+        Assert.Same(exception, context.InvokeException);
+    }
+
+    #endregion
+
    private sealed class TestAIContextProvider : AIContextProvider
    {
        public override ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
@@ -346,4 +346,91 @@ public class AgentResponseTests
        // Act & Assert.
        Assert.False(response.TryDeserialize<Animal>(TestJsonSerializerContext.Default.Options, out _));
    }
+
+    [Fact]
+    public void UserInputRequests_ReturnsEmptyWhenNoMessages()
+    {
+        // Arrange
+        AgentResponse response = new();
+
+        // Act
+        IEnumerable<UserInputRequestContent> requests = response.UserInputRequests;
+
+        // Assert
+        Assert.Empty(requests);
+    }
+
+    [Fact]
+    public void UserInputRequests_ReturnsEmptyWhenNoUserInputRequestContent()
+    {
+        // Arrange
+        AgentResponse response = new(new ChatMessage(ChatRole.Assistant, "Hello"));
+
+        // Act
+        IEnumerable<UserInputRequestContent> requests = response.UserInputRequests;
+
+        // Assert
+        Assert.Empty(requests);
+    }
+
+    [Fact]
+    public void ToAgentResponseUpdatesWithNoMessagesProducesEmptyArray()
+    {
+        // Arrange
+        AgentResponse response = new();
+
+        // Act
+        AgentResponseUpdate[] updates = response.ToAgentResponseUpdates();
+
+        // Assert
+        Assert.Empty(updates);
+    }
+
+    [Fact]
+    public void ToAgentResponseUpdatesWithUsageOnlyProducesSingleUpdate()
+    {
+        // Arrange
+        AgentResponse response = new()
+        {
+            Usage = new UsageDetails { TotalTokenCount = 100 }
+        };
+
+        // Act
+        AgentResponseUpdate[] updates = response.ToAgentResponseUpdates();
+
+        // Assert
+        AgentResponseUpdate update = Assert.Single(updates);
+        UsageContent usageContent = Assert.IsType<UsageContent>(update.Contents[0]);
+        Assert.Equal(100, usageContent.Details.TotalTokenCount);
+    }
+
+    [Fact]
+    public void ToAgentResponseUpdatesWithAdditionalPropertiesOnlyProducesSingleUpdate()
+    {
+        // Arrange
+        AgentResponse response = new()
+        {
+            AdditionalProperties = new() { ["key"] = "value" }
+        };
+
+        // Act
+        AgentResponseUpdate[] updates = response.ToAgentResponseUpdates();
+
+        // Assert
+        AgentResponseUpdate update = Assert.Single(updates);
+        Assert.NotNull(update.AdditionalProperties);
+        Assert.Equal("value", update.AdditionalProperties!["key"]);
+    }
+
+    [Fact]
+    public void Deserialize_ThrowsWhenDeserializationReturnsNull()
+    {
+        // Arrange
+        AgentResponse response = new(new ChatMessage(ChatRole.Assistant, "null"));
+
+        // Act & Assert
+        InvalidOperationException exception = Assert.Throws<InvalidOperationException>(
+            () => response.Deserialize<Animal>(TestJsonSerializerContext.Default.Options));
+        Assert.Equal("The deserialized response is null.", exception.Message);
+    }
 }
@@ -299,6 +299,161 @@ public class AgentResponseUpdateExtensionsTests
        Assert.Equal(expected, response.CreatedAt);
    }

+    #region AsChatResponse Tests
+
+    [Fact]
+    public void AsChatResponse_WithNullArgument_ThrowsArgumentNullException()
+    {
+        // Arrange & Act & Assert
+        Assert.Throws<ArgumentNullException>("response", () => ((AgentResponse)null!).AsChatResponse());
+    }
+
+    [Fact]
+    public void AsChatResponse_WithRawRepresentationAsChatResponse_ReturnsSameInstance()
+    {
+        // Arrange
+        ChatResponse originalChatResponse = new()
+        {
+            ResponseId = "original-response",
+            Messages = [new ChatMessage(ChatRole.Assistant, "Hello")]
+        };
+        AgentResponse agentResponse = new(originalChatResponse);
+
+        // Act
+        ChatResponse result = agentResponse.AsChatResponse();
+
+        // Assert
+        Assert.Same(originalChatResponse, result);
+    }
+
+    [Fact]
+    public void AsChatResponse_WithoutRawRepresentation_CreatesNewChatResponse()
+    {
+        // Arrange
+        AgentResponse agentResponse = new(new ChatMessage(ChatRole.Assistant, "Test message"))
+        {
+            ResponseId = "test-response-id",
+            CreatedAt = new DateTimeOffset(2024, 1, 1, 12, 0, 0, TimeSpan.Zero),
+            Usage = new UsageDetails { TotalTokenCount = 50 },
+            AdditionalProperties = new() { ["key"] = "value" },
+            ContinuationToken = ResponseContinuationToken.FromBytes(new byte[] { 1, 2, 3 }),
+        };
+
+        // Act
+        ChatResponse result = agentResponse.AsChatResponse();
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal("test-response-id", result.ResponseId);
+        Assert.Equal(new DateTimeOffset(2024, 1, 1, 12, 0, 0, TimeSpan.Zero), result.CreatedAt);
+        Assert.Same(agentResponse.Messages, result.Messages);
+        Assert.Same(agentResponse, result.RawRepresentation);
+        Assert.Same(agentResponse.Usage, result.Usage);
+        Assert.Same(agentResponse.AdditionalProperties, result.AdditionalProperties);
+        Assert.Equal(agentResponse.ContinuationToken, result.ContinuationToken);
+    }
+
+    #endregion
+
+    #region AsChatResponseUpdate Tests
+
+    [Fact]
+    public void AsChatResponseUpdate_WithNullArgument_ThrowsArgumentNullException()
+    {
+        // Arrange & Act & Assert
+        Assert.Throws<ArgumentNullException>("responseUpdate", () => ((AgentResponseUpdate)null!).AsChatResponseUpdate());
+    }
+
+    [Fact]
+    public void AsChatResponseUpdate_WithRawRepresentationAsChatResponseUpdate_ReturnsSameInstance()
+    {
+        // Arrange
+        ChatResponseUpdate originalChatResponseUpdate = new()
+        {
+            ResponseId = "original-update",
+            Contents = [new TextContent("Hello")]
+        };
+        AgentResponseUpdate agentResponseUpdate = new(originalChatResponseUpdate);
+
+        // Act
+        ChatResponseUpdate result = agentResponseUpdate.AsChatResponseUpdate();
+
+        // Assert
+        Assert.Same(originalChatResponseUpdate, result);
+    }
+
+    [Fact]
+    public void AsChatResponseUpdate_WithoutRawRepresentation_CreatesNewChatResponseUpdate()
+    {
+        // Arrange
+        AgentResponseUpdate agentResponseUpdate = new(ChatRole.Assistant, "Test")
+        {
+            AuthorName = "TestAuthor",
+            ResponseId = "update-id",
+            MessageId = "message-id",
+            CreatedAt = new DateTimeOffset(2024, 1, 1, 12, 0, 0, TimeSpan.Zero),
+            AdditionalProperties = new() { ["key"] = "value" },
+            ContinuationToken = ResponseContinuationToken.FromBytes(new byte[] { 1, 2, 3 }),
+        };
+
+        // Act
+        ChatResponseUpdate result = agentResponseUpdate.AsChatResponseUpdate();
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal("TestAuthor", result.AuthorName);
+        Assert.Equal("update-id", result.ResponseId);
+        Assert.Equal("message-id", result.MessageId);
+        Assert.Equal(new DateTimeOffset(2024, 1, 1, 12, 0, 0, TimeSpan.Zero), result.CreatedAt);
+        Assert.Equal(ChatRole.Assistant, result.Role);
+        Assert.Same(agentResponseUpdate.Contents, result.Contents);
+        Assert.Same(agentResponseUpdate, result.RawRepresentation);
+        Assert.Same(agentResponseUpdate.AdditionalProperties, result.AdditionalProperties);
+        Assert.Equal(agentResponseUpdate.ContinuationToken, result.ContinuationToken);
+    }
+
+    #endregion
+
+    #region AsChatResponseUpdatesAsync Tests
+
+    [Fact]
+    public async Task AsChatResponseUpdatesAsync_WithNullArgument_ThrowsArgumentNullExceptionAsync()
+    {
+        // Arrange & Act & Assert
+        await Assert.ThrowsAsync<ArgumentNullException>("responseUpdates", async () =>
+        {
+            await foreach (ChatResponseUpdate _ in ((IAsyncEnumerable<AgentResponseUpdate>)null!).AsChatResponseUpdatesAsync())
+            {
+                // Do nothing
+            }
+        });
+    }
+
+    [Fact]
+    public async Task AsChatResponseUpdatesAsync_ConvertsUpdatesAsync()
+    {
+        // Arrange
+        AgentResponseUpdate[] updates =
+        [
+            new(ChatRole.Assistant, "First"),
+            new(ChatRole.Assistant, "Second"),
+        ];
+
+        // Act
+        List<ChatResponseUpdate> results = [];
+        await foreach (ChatResponseUpdate update in YieldAsync(updates).AsChatResponseUpdatesAsync())
+        {
+            results.Add(update);
+        }
+
+        // Assert
+        Assert.Equal(2, results.Count);
+        Assert.Equal("First", Assert.IsType<TextContent>(results[0].Contents[0]).Text);
+        Assert.Equal("Second", Assert.IsType<TextContent>(results[1].Contents[0]).Text);
+    }
+
+    #endregion
+
    private static async IAsyncEnumerable<AgentResponseUpdate> YieldAsync(IEnumerable<AgentResponseUpdate> updates)
    {
        foreach (AgentResponseUpdate update in updates)
@@ -199,4 +199,30 @@ public class AgentResponseUpdateTests
        Assert.NotNull(result.ContinuationToken);
        Assert.Equivalent(ResponseContinuationToken.FromBytes(new byte[] { 1, 2, 3 }), result.ContinuationToken);
    }
+
+    [Fact]
+    public void UserInputRequests_ReturnsEmptyWhenNoContents()
+    {
+        // Arrange
+        AgentResponseUpdate update = new();
+
+        // Act
+        IEnumerable<UserInputRequestContent> requests = update.UserInputRequests;
+
+        // Assert
+        Assert.Empty(requests);
+    }
+
+    [Fact]
+    public void UserInputRequests_ReturnsEmptyWhenNoUserInputRequestContent()
+    {
+        // Arrange
+        AgentResponseUpdate update = new(ChatRole.Assistant, "Hello");
+
+        // Act
+        IEnumerable<UserInputRequestContent> requests = update.UserInputRequests;
+
+        // Assert
+        Assert.Empty(requests);
+    }
 }
@@ -76,6 +76,140 @@ public class ChatHistoryProviderTests

    #endregion

+    #region InvokingContext Tests
+
+    [Fact]
+    public void InvokingContext_Constructor_ThrowsForNullMessages()
+    {
+        // Arrange & Act & Assert
+        Assert.Throws<ArgumentNullException>(() => new ChatHistoryProvider.InvokingContext(null!));
+    }
+
+    [Fact]
+    public void InvokingContext_RequestMessages_SetterThrowsForNull()
+    {
+        // Arrange
+        var messages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var context = new ChatHistoryProvider.InvokingContext(messages);
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => context.RequestMessages = null!);
+    }
+
+    [Fact]
+    public void InvokingContext_RequestMessages_SetterRoundtrips()
+    {
+        // Arrange
+        var initialMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var newMessages = new List<ChatMessage> { new(ChatRole.User, "New message") };
+        var context = new ChatHistoryProvider.InvokingContext(initialMessages);
+
+        // Act
+        context.RequestMessages = newMessages;
+
+        // Assert
+        Assert.Same(newMessages, context.RequestMessages);
+    }
+
+    #endregion
+
+    #region InvokedContext Tests
+
+    [Fact]
+    public void InvokedContext_Constructor_ThrowsForNullRequestMessages()
+    {
+        // Arrange & Act & Assert
+        Assert.Throws<ArgumentNullException>(() => new ChatHistoryProvider.InvokedContext(null!, []));
+    }
+
+    [Fact]
+    public void InvokedContext_RequestMessages_SetterThrowsForNull()
+    {
+        // Arrange
+        var requestMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, []);
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => context.RequestMessages = null!);
+    }
+
+    [Fact]
+    public void InvokedContext_RequestMessages_SetterRoundtrips()
+    {
+        // Arrange
+        var initialMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var newMessages = new List<ChatMessage> { new(ChatRole.User, "New message") };
+        var context = new ChatHistoryProvider.InvokedContext(initialMessages, []);
+
+        // Act
+        context.RequestMessages = newMessages;
+
+        // Assert
+        Assert.Same(newMessages, context.RequestMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_ChatHistoryProviderMessages_SetterRoundtrips()
+    {
+        // Arrange
+        var requestMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var newProviderMessages = new List<ChatMessage> { new(ChatRole.System, "System message") };
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, []);
+
+        // Act
+        context.ChatHistoryProviderMessages = newProviderMessages;
+
+        // Assert
+        Assert.Same(newProviderMessages, context.ChatHistoryProviderMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_AIContextProviderMessages_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var aiContextMessages = new List<ChatMessage> { new(ChatRole.System, "AI context message") };
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, []);
+
+        // Act
+        context.AIContextProviderMessages = aiContextMessages;
+
+        // Assert
+        Assert.Same(aiContextMessages, context.AIContextProviderMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_ResponseMessages_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var responseMessages = new List<ChatMessage> { new(ChatRole.Assistant, "Response message") };
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, []);
+
+        // Act
+        context.ResponseMessages = responseMessages;
+
+        // Assert
+        Assert.Same(responseMessages, context.ResponseMessages);
+    }
+
+    [Fact]
+    public void InvokedContext_InvokeException_Roundtrips()
+    {
+        // Arrange
+        var requestMessages = new List<ChatMessage> { new(ChatRole.User, "Hello") };
+        var exception = new InvalidOperationException("Test exception");
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, []);
+
+        // Act
+        context.InvokeException = exception;
+
+        // Assert
+        Assert.Same(exception, context.InvokeException);
+    }
+
+    #endregion
+
    private sealed class TestChatHistoryProvider : ChatHistoryProvider
    {
        public override ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
@@ -2,6 +2,7 @@

 using System;
 using System.Collections.Generic;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.AI;
@@ -145,6 +146,26 @@ public class DelegatingAIAgentTests
        this._innerAgentMock.Verify(x => x.CreateSessionAsync(), Times.Once);
    }

+    /// <summary>
+    /// Verify that DeserializeSessionAsync delegates to inner agent.
+    /// </summary>
+    [Fact]
+    public async Task DeserializeSessionAsync_DelegatesToInnerAgentAsync()
+    {
+        // Arrange
+        var serializedSession = JsonSerializer.SerializeToElement("test-session-id", TestJsonSerializerContext.Default.String);
+        this._innerAgentMock
+            .Setup(x => x.DeserializeSessionAsync(It.IsAny<JsonElement>(), null, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(this._testSession);
+
+        // Act
+        var session = await this._delegatingAgent.DeserializeSessionAsync(serializedSession);
+
+        // Assert
+        Assert.Same(this._testSession, session);
+        this._innerAgentMock.Verify(x => x.DeserializeSessionAsync(It.IsAny<JsonElement>(), null, It.IsAny<CancellationToken>()), Times.Once);
+    }
+
    /// <summary>
    /// Verify that RunAsync delegates to inner agent with correct parameters.
    /// </summary>
@@ -614,6 +614,42 @@ public class InMemoryChatHistoryProviderTests
        reducerMock.Verify(r => r.ReduceAsync(It.IsAny<IEnumerable<ChatMessage>>(), It.IsAny<CancellationToken>()), Times.Never);
    }

+    [Fact]
+    public async Task InvokedAsync_WithException_DoesNotAddMessagesAsync()
+    {
+        // Arrange
+        var provider = new InMemoryChatHistoryProvider();
+        var requestMessages = new List<ChatMessage>
+        {
+            new(ChatRole.User, "Hello")
+        };
+        var responseMessages = new List<ChatMessage>
+        {
+            new(ChatRole.Assistant, "Hi there!")
+        };
+        var context = new ChatHistoryProvider.InvokedContext(requestMessages, [])
+        {
+            ResponseMessages = responseMessages,
+            InvokeException = new InvalidOperationException("Test exception")
+        };
+
+        // Act
+        await provider.InvokedAsync(context, CancellationToken.None);
+
+        // Assert
+        Assert.Empty(provider);
+    }
+
+    [Fact]
+    public async Task InvokingAsync_WithNullContext_ThrowsArgumentNullExceptionAsync()
+    {
+        // Arrange
+        var provider = new InMemoryChatHistoryProvider();
+
+        // Act & Assert
+        await Assert.ThrowsAsync<ArgumentNullException>(() => provider.InvokingAsync(null!, CancellationToken.None).AsTask());
+    }
+
    public class TestAIContent(string testData) : AIContent
    {
        public string TestData => testData;