refactor: organize test project structure

SongTidy.Tests/Services/AudioFileScannerTests.cs

@@ -0,0 +1,65 @@
+using System.IO;
+using System.Linq;
+
+using SongTidy.Services;
+using SongTidy.Tests.TestUtilities;
+
+namespace SongTidy.Tests.Services;
+
+/// <summary>
+/// Contains tests for <see cref="AudioFileScanner"/>.
+/// </summary>
+[TestClass]
+public sealed class AudioFileScannerTests {
+    private readonly TempDirectory _tempDirectory = new();
+
+    /// <summary>
+    /// Removes the temporary directory created for the current test.
+    /// </summary>
+    [TestCleanup]
+    public void Cleanup() {
+        _tempDirectory.Dispose();
+    }
+
+    /// <summary>
+    /// Verifies that supported extensions are matched case-insensitively and others are ignored.
+    /// </summary>
+    [TestMethod]
+    public void ScansSupportedExtensionsCaseInsensitively() {
+        CreateFile("a.mp3");
+        CreateFile("b.FLAC");
+        CreateFile("c.txt");
+
+        IReadOnlyList<string> files = AudioFileScanner.Scan(_tempDirectory.FullPath);
+
+        Assert.HasCount(2, files);
+        Assert.IsTrue(files.Any(file => file.EndsWith("a.mp3", StringComparison.OrdinalIgnoreCase)));
+        Assert.IsTrue(files.Any(file => file.EndsWith("b.FLAC", StringComparison.OrdinalIgnoreCase)));
+    }
+
+    /// <summary>
+    /// Verifies that subdirectories are not scanned.
+    /// </summary>
+    [TestMethod]
+    public void DoesNotScanSubdirectories() {
+        CreateFile("root.mp3");
+        CreateFile(Path.Combine("sub", "nested.wav"));
+
+        IReadOnlyList<string> files = AudioFileScanner.Scan(_tempDirectory.FullPath);
+
+        Assert.HasCount(1, files);
+        Assert.IsTrue(files[0].EndsWith("root.mp3", StringComparison.OrdinalIgnoreCase));
+    }
+
+    /// <summary>
+    /// Creates an empty file inside the test directory.
+    /// </summary>
+    /// <param name="fileName">The relative file name, which may include a subdirectory.</param>
+    private void CreateFile(string fileName) {
+        string path = Path.Combine(_tempDirectory.FullPath, fileName);
+        string directory = Path.GetDirectoryName(path) ?? _tempDirectory.FullPath;
+
+        Directory.CreateDirectory(directory);
+        File.WriteAllText(path, string.Empty);
+    }
+}