Added backups of all data, restorable on another computer (#1008)

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

app/Tests/Chat/ManagedTranscriptAttachmentTests.cs

@@ -0,0 +1,104 @@
+using AIStudio.Chat;
+using AIStudio.Settings;
+
+namespace AIStudio.Tests.Chat;
+
+/// <summary>
+/// Checks which transcript files AI Studio deletes as its own.
+/// </summary>
+/// <remarks>
+/// A transcript carries a full path, which a chat file edited outside the app may point anywhere. AI
+/// Studio therefore deletes a file only where it keeps transcripts itself: in the transcript folder of a
+/// chat, or in the staging area.
+/// </remarks>
+[TestFixture]
+[NonParallelizable]
+public sealed class ManagedTranscriptAttachmentTests
+{
+    private string? previousDataDirectory;
+    private string testDirectory = string.Empty;
+
+    [SetUp]
+    public void PrepareDataDirectory()
+    {
+        // The data directory is static state of the whole application, which is why this fixture does not run alongside others:
+        this.previousDataDirectory = SettingsManager.DataDirectory;
+        this.testDirectory = Path.Combine(Path.GetTempPath(), $"ai-studio-transcripts-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(this.testDirectory);
+        SettingsManager.DataDirectory = this.testDirectory;
+    }
+
+    [TearDown]
+    public void RemoveDataDirectory()
+    {
+        SettingsManager.DataDirectory = this.previousDataDirectory;
+
+        try
+        {
+            Directory.Delete(this.testDirectory, true);
+        }
+        catch (IOException)
+        {
+            // A temporary directory we could not remove says nothing about the code under test.
+        }
+    }
+
+    [Test]
+    public void TheTranscriptOfAWorkspaceChatIsDeleted()
+    {
+        var chatDirectory = Path.Combine(this.testDirectory, "workspaces", Guid.NewGuid().ToString(), Guid.NewGuid().ToString());
+        var transcript = WriteTranscript(ManagedTranscriptAttachment.GetTranscriptDirectory(chatDirectory));
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(ManagedTranscriptAttachment.TryDeleteOwnedFile(transcript), Is.True);
+            Assert.That(File.Exists(transcript.FilePath), Is.False);
+        });
+    }
+
+    [Test]
+    public void AFileInAnotherFolderOfTheChatStays()
+    {
+        var chatDirectory = Path.Combine(this.testDirectory, "workspaces", Guid.NewGuid().ToString(), Guid.NewGuid().ToString());
+        var file = WriteTranscript(Path.Combine(chatDirectory, "attachments", "images"));
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(ManagedTranscriptAttachment.TryDeleteOwnedFile(file), Is.False, "Only the transcript folder belongs to the transcripts.");
+            Assert.That(File.Exists(file.FilePath), Is.True);
+        });
+    }
+
+    [Test]
+    public void AFileOutsideTheDataDirectoryStays()
+    {
+        var outsideDirectory = Path.Combine(Path.GetTempPath(), $"ai-studio-elsewhere-{Guid.NewGuid():N}");
+        try
+        {
+            var file = WriteTranscript(ManagedTranscriptAttachment.GetTranscriptDirectory(Path.Combine(outsideDirectory, "tempChats", Guid.NewGuid().ToString())));
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(ManagedTranscriptAttachment.TryDeleteOwnedFile(file), Is.False, "The same folders elsewhere belong to somebody else.");
+                Assert.That(File.Exists(file.FilePath), Is.True);
+            });
+        }
+        finally
+        {
+            Directory.Delete(outsideDirectory, true);
+        }
+    }
+
+    /// <summary>
+    /// Writes a transcript into a folder.
+    /// </summary>
+    /// <param name="directory">Where the transcript goes.</param>
+    /// <returns>The transcript, as a chat attaches it to a message.</returns>
+    private static ManagedTranscriptAttachment WriteTranscript(string directory)
+    {
+        Directory.CreateDirectory(directory);
+        var path = Path.Combine(directory, "meeting-transcript-0001.md");
+        File.WriteAllText(path, "# Transcription: meeting.mp4");
+        return new ManagedTranscriptAttachment(Path.GetFileName(path), path, new FileInfo(path).Length, "meeting.mp4", false);
+    }
+}