Added an overview of all files attached to a chat (#1002)

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

app/Tests/Chat/ChatThreadSentFileAttachmentsTests.cs

@@ -0,0 +1,117 @@
+using AIStudio.Chat;
+
+namespace AIStudio.Tests.Chat;
+
+/// <summary>
+/// Checks which attachments the overview of all files of a chat lists.
+/// </summary>
+/// <remarks>
+/// Every message keeps the text its documents were sent with. A file changed between two messages
+/// reached the AI in two versions, and the overview has to show both, while a file sent again
+/// unchanged is one version only.
+/// </remarks>
+[TestFixture]
+public sealed class ChatThreadSentFileAttachmentsTests
+{
+    private static readonly DateTimeOffset START = new(2026, 10, 16, 9, 0, 0, TimeSpan.Zero);
+
+    private static readonly string MINUTES_PATH = Path.Combine(Path.GetTempPath(), "board", "minutes.txt");
+
+    private static readonly FileVersion FIRST_VERSION = new(new DateTime(2026, 10, 15, 8, 0, 0, DateTimeKind.Utc), 120);
+
+    private static readonly FileVersion SECOND_VERSION = new(new DateTime(2026, 11, 5, 17, 30, 0, DateTimeKind.Utc), 180);
+
+    [Test]
+    public void AFileChangedBetweenTwoMessagesAppearsInBothVersions()
+    {
+        var first = Minutes(FIRST_VERSION);
+        var second = Minutes(SECOND_VERSION);
+        var thread = Thread(Message(1, first), Message(2, second));
+
+        var attachments = thread.CollectSentFileAttachments();
+
+        Assert.That(attachments, Is.EquivalentTo([first, second]), "The AI received both versions, so the overview has to show both.");
+    }
+
+    [Test]
+    public void AFileSentAgainUnchangedAppearsOnceWithItsLatestMessage()
+    {
+        var earlier = Minutes(FIRST_VERSION);
+        var later = Minutes(FIRST_VERSION);
+
+        // The chat orders its messages by their time, not by their place in the list:
+        var thread = Thread(Message(2, later), Message(1, earlier));
+
+        var attachments = thread.CollectSentFileAttachments();
+
+        Assert.That(attachments, Is.EquivalentTo([later]));
+    }
+
+    [Test]
+    public void AnAttachmentWithoutANotedStateAppearsOncePerPath()
+    {
+        var imagePath = Path.Combine(Path.GetTempPath(), "board", "chart.png");
+        var thread = Thread(Message(1, new FileAttachmentImage("chart.png", imagePath, 2048)), Message(2, new FileAttachmentImage("chart.png", imagePath, 4096)));
+
+        var attachments = thread.CollectSentFileAttachments();
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(attachments, Has.Count.EqualTo(1), "Every request reads such a file anew, so there is only one version of it.");
+            Assert.That(attachments.Single().FileSizeBytes, Is.EqualTo(4096), "The latest message names the file as it was last.");
+        }
+    }
+
+    [Test]
+    public void TheDraftAndTheHiddenMessagesAreLeftOut()
+    {
+        var thread = Thread(HiddenMessage(1, Minutes(FIRST_VERSION)), Message(2));
+        thread.Draft.MirrorAttachments([Minutes(SECOND_VERSION)]);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(thread.HasSentFileAttachments(), Is.False);
+            Assert.That(thread.CollectSentFileAttachments(), Is.Empty);
+        }
+    }
+
+    [Test]
+    public void AMessageWithAFileCountsAsSent()
+    {
+        var thread = Thread(Message(1), Message(2, Minutes(FIRST_VERSION)));
+        Assert.That(thread.HasSentFileAttachments(), Is.True);
+    }
+
+    [Test]
+    public void AChatWithoutAttachmentsHasNone()
+    {
+        var thread = Thread(Message(1), Message(2));
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(thread.HasSentFileAttachments(), Is.False);
+            Assert.That(thread.CollectSentFileAttachments(), Is.Empty);
+        }
+    }
+
+    private static FileAttachment Minutes(FileVersion version) => new(FileAttachmentType.DOCUMENT, "minutes.txt", MINUTES_PATH, version.Length)
+    {
+        ProvenanceId = Guid.NewGuid(),
+        Version = version,
+    };
+
+    private static ChatThread Thread(params ContentBlock[] blocks) => new() { Blocks = [..blocks] };
+
+    private static ContentBlock Message(int minute, params FileAttachment[] attachments) => Block(minute, false, attachments);
+
+    private static ContentBlock HiddenMessage(int minute, params FileAttachment[] attachments) => Block(minute, true, attachments);
+
+    private static ContentBlock Block(int minute, bool hidden, FileAttachment[] attachments) => new()
+    {
+        Time = START.AddMinutes(minute),
+        ContentType = ContentType.TEXT,
+        Content = new ContentText { Text = "Please have a look.", FileAttachments = [..attachments] },
+        Role = ChatRole.USER,
+        HideFromUser = hidden,
+    };
+}