feat: extract audio conversion to separate class and refine audio extraction

2025-07-27 23:33:05 -05:00
parent a53b3893ad
commit a1864371dd
10 changed files with 199 additions and 35 deletions
@@ -1,8 +1,18 @@
+using System.Text;
+
+using StreamShorts.Library.Media;
+
 namespace StreamShorts.Library.Tests.Unit.Media.Audio;

 public class AudioExtractorTests
 {
-  private readonly AudioExtractor _sut = new();
+  private readonly Mock<IFFMpegService> _mockFfmpegService = new();
+  private readonly AudioExtractor _sut;
+
+  public AudioExtractorTests()
+  {
+    _sut = new(_mockFfmpegService.Object);
+  }

  [Fact]
  public async Task ExtractMp3FromMp4Async_WhenVideoIsNull_ItShouldThrow()
@@ -33,4 +43,93 @@ public class AudioExtractorTests

    await action.Should().ThrowAsync<ArgumentException>();
  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenFFMpegServiceThrows_ItShouldThrow()
+  {
+    var mockStream = new Mock<Stream>();
+    mockStream.Setup(static s => s.CanRead).Returns(true);
+    mockStream.Setup(static s => s.CanSeek).Returns(true);
+
+    _mockFfmpegService.
+      Setup(
+        static m => m.ExtractAudioFromVideoAsync(
+          It.IsAny<Stream>(),
+          It.IsAny<Stream>()
+        )
+      )
+      .ThrowsAsync(new Exception());
+
+    var action = async () => await _sut.ExtractMp3FromMp4Async(mockStream.Object);
+
+    await action.Should().ThrowAsync<FailedAudioExtractionException>();
+  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenFFMpegServiceFailsExtraction_ItShouldThrow()
+  {
+    var mockStream = new Mock<Stream>();
+    mockStream.Setup(static s => s.CanRead).Returns(true);
+    mockStream.Setup(static s => s.CanSeek).Returns(true);
+
+    _mockFfmpegService.
+      Setup(
+        static m => m.ExtractAudioFromVideoAsync(
+          It.IsAny<Stream>(),
+          It.IsAny<Stream>()
+        )
+      )
+      .ReturnsAsync(false);
+
+    var action = async () => await _sut.ExtractMp3FromMp4Async(mockStream.Object);
+
+    await action.Should().ThrowAsync<FailedAudioExtractionException>();
+  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenFFMpegServiceSucceedsAtExtractingAudio_ItShouldReturnStream()
+  {
+    var mockStream = new Mock<Stream>();
+    mockStream.Setup(static s => s.CanRead).Returns(true);
+    mockStream.Setup(static s => s.CanSeek).Returns(true);
+
+    _mockFfmpegService.
+      Setup(
+        static m => m.ExtractAudioFromVideoAsync(
+          It.IsAny<Stream>(),
+          It.IsAny<Stream>()
+        )
+      )
+      .ReturnsAsync(true);
+
+    var result = await _sut.ExtractMp3FromMp4Async(mockStream.Object);
+
+    result.Should().BeAssignableTo<Stream>();
+    result.Should().BeOfType<MemoryStream>();
+  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenCalled_ItShouldNotMutatePositionOfPassedStream()
+  {
+    var text = "hello world";
+    var textByte = Encoding.UTF8.GetBytes(text);
+    var stream = new MemoryStream(textByte);
+
+    var positionToRead = 5;
+    var buffer = new byte[5];
+    await stream.ReadAsync(buffer.AsMemory(0, positionToRead), TestContext.Current.CancellationToken);
+
+    _mockFfmpegService.
+      Setup(
+        static m => m.ExtractAudioFromVideoAsync(
+          It.IsAny<Stream>(),
+          It.IsAny<Stream>()
+        )
+      )
+      .ReturnsAsync(true);
+
+    await _sut.ExtractMp3FromMp4Async(stream);
+
+    stream.Position.Should().Be(positionToRead);
+  }
 }