feat: implement main window view models

SongTidy.Tests/SongEntryViewModelTests.cs

@@ -0,0 +1,163 @@
+using System.IO;
+
+using SongTidy.Models;
+using SongTidy.ViewModels;
+
+namespace SongTidy.Tests;
+
+/// <summary>
+/// Contains tests for <see cref="SongEntryViewModel"/>.
+/// </summary>
+[TestClass]
+public sealed class SongEntryViewModelTests {
+    #region Preview
+
+    /// <summary>
+    /// Verifies the initial fields and target preview.
+    /// </summary>
+    [TestMethod]
+    public void InitializesFieldsAndTargetPreview() {
+        SongEntryViewModel entry = CreateEntry();
+
+        Assert.AreEqual("Artist", entry.Artist);
+        Assert.AreEqual("Title", entry.Title);
+        Assert.AreEqual("Live", entry.Comment);
+        Assert.AreEqual(RenameFormat.ArtistFirst, entry.Format);
+        Assert.AreEqual("A.mp3", entry.OriginalFileName);
+        Assert.AreEqual("Artist - Title (Live).mp3", entry.TargetFileName);
+    }
+
+    /// <summary>
+    /// Verifies that changing a field immediately updates the target preview.
+    /// </summary>
+    [TestMethod]
+    public void UpdatesTargetPreviewWhenFieldChanges() {
+        SongEntryViewModel entry = CreateEntry();
+
+        entry.Artist = "New Artist";
+
+        Assert.AreEqual("New Artist - Title (Live).mp3", entry.TargetFileName);
+    }
+
+    /// <summary>
+    /// Verifies that changing the format updates the target preview.
+    /// </summary>
+    [TestMethod]
+    public void UpdatesTargetPreviewWhenFormatChanges() {
+        SongEntryViewModel entry = CreateEntry();
+
+        entry.Format = RenameFormat.TitleFirst;
+
+        Assert.AreEqual("Title (Live) - Artist.mp3", entry.TargetFileName);
+    }
+
+    /// <summary>
+    /// Verifies that the original extension is preserved for other file types.
+    /// </summary>
+    [TestMethod]
+    public void PreservesOriginalExtension() {
+        SongEntryViewModel entry = new(
+            Path.Combine("Music", "A.flac"),
+            string.Empty,
+            "Title",
+            string.Empty,
+            RenameFormat.ArtistFirst);
+
+        Assert.AreEqual("Title.flac", entry.TargetFileName);
+    }
+
+    #endregion
+
+    #region Dirty notifications
+
+    /// <summary>
+    /// Verifies that editing any field raises the edited event.
+    /// </summary>
+    [TestMethod]
+    public void RaisesEditedWhenFieldChanges() {
+        SongEntryViewModel entry = CreateEntry();
+        int editCount = 0;
+        entry.Edited += (_, _) => editCount++;
+
+        entry.Artist = "New Artist";
+        entry.Title = "New Title";
+        entry.Comment = "New Comment";
+
+        Assert.AreEqual(3, editCount);
+    }
+
+    /// <summary>
+    /// Verifies that assigning the current value does not raise the edited event.
+    /// </summary>
+    [TestMethod]
+    public void DoesNotRaiseEditedWhenFieldValueIsUnchanged() {
+        SongEntryViewModel entry = CreateEntry();
+        int editCount = 0;
+        entry.Edited += (_, _) => editCount++;
+
+        entry.Artist = entry.Artist;
+
+        Assert.AreEqual(0, editCount);
+    }
+
+    /// <summary>
+    /// Verifies that changing the format does not itself count as a field edit.
+    /// </summary>
+    [TestMethod]
+    public void ChangingFormatDoesNotRaiseEdited() {
+        SongEntryViewModel entry = CreateEntry();
+        int editCount = 0;
+        entry.Edited += (_, _) => editCount++;
+
+        entry.Format = RenameFormat.TitleFirst;
+
+        Assert.AreEqual(0, editCount);
+    }
+
+    #endregion
+
+    #region Swap
+
+    /// <summary>
+    /// Verifies that swapping exchanges the artist and title values.
+    /// </summary>
+    [TestMethod]
+    public void SwapsArtistAndTitle() {
+        SongEntryViewModel entry = CreateEntry();
+
+        entry.SwapArtistAndTitle();
+
+        Assert.AreEqual("Title", entry.Artist);
+        Assert.AreEqual("Artist", entry.Title);
+        Assert.AreEqual("Title - Artist (Live).mp3", entry.TargetFileName);
+    }
+
+    /// <summary>
+    /// Verifies that swapping raises edited notifications for both changed fields.
+    /// </summary>
+    [TestMethod]
+    public void SwapRaisesEditedForBothFields() {
+        SongEntryViewModel entry = CreateEntry();
+        int editCount = 0;
+        entry.Edited += (_, _) => editCount++;
+
+        entry.SwapArtistAndTitle();
+
+        Assert.AreEqual(2, editCount);
+    }
+
+    #endregion
+
+    /// <summary>
+    /// Creates a standard test entry.
+    /// </summary>
+    /// <returns>The created entry.</returns>
+    private static SongEntryViewModel CreateEntry() {
+        return new SongEntryViewModel(
+            Path.Combine("Music", "A.mp3"),
+            "Artist",
+            "Title",
+            "Live",
+            RenameFormat.ArtistFirst);
+    }
+}