Added the Model Comparison assistant for blind comparisons of two models (#1009)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/Tests/Chat/ChatTranscriptTests.cs

@@ -0,0 +1,77 @@
+using AIStudio.Chat;
+using AIStudio.Tools.ToolCallingSystem;
+
+namespace AIStudio.Tests.Chat;
+
+/// <summary>
+/// Checks that a transcript holds what the user sees of a chat, and nothing else.
+/// </summary>
+[TestFixture]
+public sealed class ChatTranscriptTests
+{
+    [Test]
+    public void TheTranscriptHoldsTheVisibleMessagesInTheirOrder()
+    {
+        var thread = Thread(
+            Block(ChatRole.USER, new ContentText { Text = "A hidden opening." }, hidden: true),
+            Block(ChatRole.USER, new ContentText { Text = "Summarize the report." }),
+            Block(ChatRole.AI, new ContentText { Text = "<think>Let me read it.</think>The report says 42." }),
+            Block(ChatRole.USER, new ContentText { Text = "Thanks." }));
+
+        Assert.That(ChatTranscript.Of(thread), Is.EqualTo("[User]\nSummarize the report.\n\n[Assistant]\nThe report says 42.\n\n[User]\nThanks."));
+    }
+
+    [Test]
+    public void ToolCallsAreOneShortLineWithoutTheirResults()
+    {
+        var answer = new ContentText
+        {
+            Text = "Found it.",
+            ToolInvocations =
+            [
+                new ToolInvocationTrace { Order = 2, ToolName = "read_web_page", Arguments = new() { ["url"] = "https://example.org" }, Result = "The whole page." },
+                new ToolInvocationTrace { Order = 1, ToolName = "web_search", Arguments = new() { ["query"] = new string('q', 100) + "\nmore" }, Result = "Many results." },
+            ],
+        };
+
+        var transcript = ChatTranscript.Of(Thread(Block(ChatRole.AI, answer)));
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(transcript, Does.StartWith($"[Assistant]\n[Tool call: web_search(query={new string('q', ChatTranscript.MAX_ARGUMENT_LENGTH)}…)]\n[Tool call: read_web_page(url=https://example.org)]\nFound it."));
+            Assert.That(transcript, Does.Not.Contain("Many results."));
+            Assert.That(transcript, Does.Not.Contain("The whole page."));
+        }
+    }
+
+    [Test]
+    public void AttachedFilesAreNamedWithoutTheirContent()
+    {
+        var message = new ContentText
+        {
+            Text = "Please check these.",
+            FileAttachments = [new FileAttachment(FileAttachmentType.DOCUMENT, "report.pdf", "/tmp/report.pdf", 100), new FileAttachment(FileAttachmentType.DOCUMENT, "notes.md", "/tmp/notes.md", 10)],
+        };
+
+        Assert.That(ChatTranscript.Of(Thread(Block(ChatRole.USER, message))), Is.EqualTo("[User]\nPlease check these.\n[Attached files: report.pdf, notes.md]"));
+    }
+
+    [Test]
+    public void AChatWithoutVisibleMessagesHasAnEmptyTranscript()
+    {
+        var thread = Thread(Block(ChatRole.AI, new ContentText { Text = "   " }), Block(ChatRole.USER, new ContentText { Text = "Hidden." }, hidden: true));
+
+        Assert.That(ChatTranscript.Of(thread), Is.Empty);
+    }
+
+    private static ChatThread Thread(params ContentBlock[] blocks) => new() { Blocks = [.. blocks] };
+
+    private static ContentBlock Block(ChatRole role, ContentText content, bool hidden = false) => new()
+    {
+        Time = DateTimeOffset.UnixEpoch,
+        ContentType = ContentType.TEXT,
+        Role = role,
+        Content = content,
+        HideFromUser = hidden,
+    };
+}