Added transcription of audio and video files to local data sources (#1081)

Co-authored-by: Paul Koudelka <106623909+PaulKoudelka@users.noreply.github.com>

app/Tests/Tools/Media/MediaSidecarTranscriptsTests.cs

@@ -0,0 +1,57 @@
+using AIStudio.Tools.Media;
+
+namespace AIStudio.Tests.Tools.Media;
+
+/// <summary>
+/// Checks the transcripts which the Batch Processing assistant keeps next to its media files.
+/// </summary>
+[TestFixture]
+public sealed class MediaSidecarTranscriptsTests
+{
+    [TestCase("recording.mp3.transcript.md")]
+    [TestCase("recording.mp3.transcript.md.0123456789abcdef.tmp")]
+    [TestCase("RECORDING.MP3.TRANSCRIPT.MD")]
+    public void GeneratedTranscriptFilesAreRecognized(string fileName)
+    {
+        Assert.That(MediaSidecarTranscripts.IsArtifactPath(fileName), Is.True);
+    }
+
+    [TestCase("notes.md")]
+    [TestCase("recording.mp3")]
+    [TestCase("recording.mp3.transcript.md.backup")]
+    public void OtherFilesAreNoTranscripts(string fileName)
+    {
+        Assert.That(MediaSidecarTranscripts.IsArtifactPath(fileName), Is.False);
+    }
+
+    [Test]
+    public async Task TheTranscriptLiesNextToItsMediaFile()
+    {
+        var mediaPath = Path.Combine(Path.GetTempPath(), "recording.mp3");
+        var slot = await MediaSidecarTranscripts.INSTANCE.ResolveAsync(mediaPath, CancellationToken.None);
+        Assert.That(slot.Path, Is.EqualTo(mediaPath + MediaSidecarTranscripts.FILE_SUFFIX));
+    }
+
+    [Test]
+    public async Task OnlyATranscriptWithContentCanBeReused()
+    {
+        var directoryPath = Path.Combine(Path.GetTempPath(), $"ai-studio-sidecar-transcript-{Guid.NewGuid():N}");
+        var mediaPath = Path.Combine(directoryPath, "recording.mp3");
+        Directory.CreateDirectory(directoryPath);
+
+        try
+        {
+            Assert.That(MediaSidecarTranscripts.HasReusableTranscript(mediaPath), Is.False, "A missing transcript counted as reusable.");
+
+            await File.WriteAllTextAsync(MediaSidecarTranscripts.GetFilePath(mediaPath), string.Empty);
+            Assert.That(MediaSidecarTranscripts.HasReusableTranscript(mediaPath), Is.False, "An empty transcript counted as reusable.");
+
+            await File.WriteAllTextAsync(MediaSidecarTranscripts.GetFilePath(mediaPath), "Transcript");
+            Assert.That(MediaSidecarTranscripts.HasReusableTranscript(mediaPath), Is.True);
+        }
+        finally
+        {
+            Directory.Delete(directoryPath, true);
+        }
+    }
+}