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/Embedded/EmbeddedChatOpeningTests.cs

@@ -0,0 +1,71 @@
+using AIStudio.Chat;
+using AIStudio.Chat.Embedded;
+
+namespace AIStudio.Tests.Chat.Embedded;
+
+/// <summary>
+/// Checks when an embedded chat sends the message it opens with.
+/// </summary>
+[TestFixture]
+public sealed class EmbeddedChatOpeningTests
+{
+    private static readonly ContentText OPENING_MESSAGE = new() { Text = "What is new today?" };
+
+    [Test]
+    public void AnEmptyChatSendsItsOpeningMessage()
+    {
+        Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, Conversation(), wasSent: false), Is.True);
+    }
+
+    [Test]
+    public void AChatWithoutOpeningMessageSendsNothing()
+    {
+        Assert.That(EmbeddedChatOpening.SendsNow(null, Conversation(), wasSent: false), Is.False);
+    }
+
+    [Test]
+    public void AChatSendsItsOpeningMessageOnlyOnce()
+    {
+        // Until the request adds the message to the chat, the chat still looks empty:
+        Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, Conversation(), wasSent: true), Is.False);
+    }
+
+    [Test]
+    public void AChatInWhichTheUserWroteSendsNothing()
+    {
+        var conversation = Conversation();
+        conversation.Thread!.Blocks.Add(new ContentBlock { Role = ChatRole.USER, ContentType = ContentType.TEXT, Content = new ContentText { Text = "My own question." } });
+
+        Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, conversation, wasSent: false), Is.False);
+    }
+
+    [Test]
+    public void AChatWhichLoadsOrCannotBeOpenedSendsNothing()
+    {
+        var unavailable = Conversation();
+        unavailable.Thread = null;
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, null, wasSent: false), Is.False, "While the chat loads, the message waits.");
+            Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, unavailable, wasSent: false), Is.False);
+        }
+    }
+
+    [Test]
+    public void AChatInWhichTheModelAnswersSendsNothing()
+    {
+        var conversation = Conversation();
+        conversation.IsRunning = true;
+
+        Assert.That(EmbeddedChatOpening.SendsNow(OPENING_MESSAGE, conversation, wasSent: false), Is.False);
+    }
+
+    private static EmbeddedConversation Conversation() => new()
+    {
+        ChatId = Guid.NewGuid(),
+        Component = AIStudio.Tools.Components.MODEL_COMPARISON_ASSISTANT,
+        Store = new InMemoryEmbeddedChatStore(),
+        Thread = new ChatThread(),
+    };
+}