Added a way to read what the AI received from your sources (#1100)

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

app/Tests/Chat/ContentBlockApartFromChatTests.cs

@@ -0,0 +1,62 @@
+using AIStudio.Chat;
+using AIStudio.Tools.RAG;
+
+namespace AIStudio.Tests.Chat;
+
+/// <summary>
+/// Checks what a block keeps when it leaves its chat, e.g., for the example conversation of a chat template.
+/// </summary>
+/// <remarks>
+/// What a chat received lies in the provenance store and is deleted with the chat. A template made
+/// from a chat, and every chat started from that template, must not refer to it: they would lose
+/// their passages and attachments as soon as the first chat is deleted.
+/// </remarks>
+[TestFixture]
+public sealed class ContentBlockApartFromChatTests
+{
+    [Test]
+    public void ABlockApartFromItsChatRefersToNothingOfItsStore()
+    {
+        var chat = new ChatThread { ChatId = Guid.NewGuid(), Blocks = [Question(Guid.NewGuid()), Answer(Guid.NewGuid())] };
+
+        var template = new ChatThread { ChatId = Guid.NewGuid(), Blocks = chat.Blocks.Select(block => block.CloneApartFromChat()).ToList() };
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(template.CollectProvenanceIds(), Is.Empty, "The entries belong to the chat and are deleted with it.");
+            Assert.That(template.Blocks.Select(block => ((ContentText)block.Content!).Text), Is.EqualTo(new[] { "Summarize the minutes.", "The board met on Monday." }));
+            Assert.That(template.Blocks[0].Content!.FileAttachments.Select(attachment => attachment.FilePath), Is.EqualTo(new[] { "/tmp/minutes.txt" }), "The file is read anew by every chat it reaches.");
+            Assert.That(chat.CollectProvenanceIds(), Has.Count.EqualTo(2), "The chat itself keeps what it received.");
+        });
+    }
+
+    [Test]
+    public void ABlockApartFromItsChatCanBeHidden()
+    {
+        var visible = new ContentBlock { ContentType = ContentType.TEXT, Role = ChatRole.USER, Content = new ContentText { Text = "Hello" } };
+
+        Assert.That(visible.CloneApartFromChat(true).HideFromUser, Is.True, "A template made from a chat hides its blocks, as before.");
+    }
+
+    private static ContentBlock Question(Guid attachmentId) => new()
+    {
+        ContentType = ContentType.TEXT,
+        Role = ChatRole.USER,
+        Content = new ContentText
+        {
+            Text = "Summarize the minutes.",
+            FileAttachments = [new FileAttachment(FileAttachmentType.DOCUMENT, "minutes.txt", "/tmp/minutes.txt", 24) { ProvenanceId = attachmentId }],
+        },
+    };
+
+    private static ContentBlock Answer(Guid passageId) => new()
+    {
+        ContentType = ContentType.TEXT,
+        Role = ChatRole.AI,
+        Content = new ContentText
+        {
+            Text = "The board met on Monday.",
+            SourcePassages = [new SourcePassage { SourceUrl = "file:///C:/docs/minutes.pdf", ProvenanceId = passageId }],
+        },
+    };
+}