/* *******************************************************************************************************************

* Application: ClaudeCodeExtension

*

* Autor: Daniel Carvalho Liedke / Claude Code

*

* Copyright © Daniel Carvalho Liedke 2026

* Usage and reproduction in any manner whatsoever without the written permission of Daniel Carvalho Liedke is strictly forbidden.

*

* Purpose: Covers the throttled Text change notifications of a streaming chat row: the first chunk shows at once,

* later ones are announced together, reads always see everything appended, and Complete flushes.

*

* *******************************************************************************************************************/

using System;

using System.Collections.Generic;

using ClaudeCodeVS.UI;

using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace ClaudeCodeExtension.Tests

{

[TestClass]

public class ChatStreamingThrottleTests

{

private TimeSpan _originalInterval;

[TestInitialize]

public void SaveInterval()

{

_originalInterval = ChatMessageViewModel.StreamingPublishInterval;

}

[TestCleanup]

public void RestoreInterval()

{

ChatMessageViewModel.StreamingPublishInterval = _originalInterval;

}

private static List<string> TrackChanges(ChatMessageViewModel message)

{

var changes = new List<string>();

message.PropertyChanged += (s, e) => changes.Add(e.PropertyName);

return changes;

}

[TestMethod]

public void FirstChunkIsAnnouncedAtOnceAndTheRestAreHeldBack()

{

// Long enough that no test machine can stall past it between two Append calls.

ChatMessageViewModel.StreamingPublishInterval = TimeSpan.FromHours(1);

var message = new ChatMessageViewModel(ChatMessageKind.Assistant) { IsStreaming = true };

List<string> changes = TrackChanges(message);

message.Append("Hel");

message.Append("lo");

message.Append(" world");

Assert.AreEqual(1, changes.FindAll(name => name == nameof(ChatMessageViewModel.Text)).Count);

// A read never sees a stale value, announced or not.

Assert.AreEqual("Hello world", message.Text);

}

[TestMethod]

public void CompleteAnnouncesTheHeldBackTextAndRendersAllOfIt()

{

ChatMessageViewModel.StreamingPublishInterval = TimeSpan.FromHours(1);

var message = new ChatMessageViewModel(ChatMessageKind.Assistant) { IsStreaming = true };

message.Append("**bold**");

List<string> changes = TrackChanges(message);

message.Append(" and the rest");

message.Complete();

Assert.AreEqual(1, changes.FindAll(name => name == nameof(ChatMessageViewModel.Text)).Count);

Assert.AreEqual("**bold** and the rest", message.RenderedText);

Assert.IsFalse(message.IsStreaming);

}

[TestMethod]

public void EveryChunkIsAnnouncedWithoutAnInterval()

{

ChatMessageViewModel.StreamingPublishInterval = TimeSpan.Zero;

var message = new ChatMessageViewModel(ChatMessageKind.Assistant) { IsStreaming = true };

List<string> changes = TrackChanges(message);

message.Append("a");

message.Append("b");

message.Append("c");

Assert.AreEqual(3, changes.FindAll(name => name == nameof(ChatMessageViewModel.Text)).Count);

Assert.AreEqual("abc", message.Text);

}

[TestMethod]

public void ReplaceTextWinsOverHeldBackChunks()

{

ChatMessageViewModel.StreamingPublishInterval = TimeSpan.FromHours(1);

var message = new ChatMessageViewModel(ChatMessageKind.Assistant) { IsStreaming = true };

message.Append("draft");

message.Append(" still streaming");

message.ReplaceText("final");

message.Complete();

Assert.AreEqual("final", message.Text);

Assert.AreEqual("final", message.RenderedText);

}

}

}