Music never falls silent (TrackPicker); mod unit tests

tests/TrackPickerTests.cs

@@ -0,0 +1,27 @@
+namespace Cthangover.Mods.Audio.Tests
+{
+    using System;
+    using System.Collections.Generic;
+    using Cthangover.Core.Mods.Testing;
+
+    /// <summary>
+    /// Choosing the next track never fails: it avoids repeating the last one
+    /// when anything else is available, and a bucket made of one track (or of
+    /// copies of it) still plays instead of falling silent.
+    /// </summary>
+    public class TrackPickerTests
+    {
+        [ModTest("music/next_track_avoids_repeat_and_never_gives_up")]
+        static void NextTrackAvoidsRepeat(ModTestContext ctx)
+        {
+            var random = new Random(3);
+            var list = new List<string> { "a", "b" };
+            for (var i = 0; i < 200; i++)
+                ModAssert.Equal("b", TrackPicker.Next(list, "a", random), "the other track");
+
+            ModAssert.Equal("a", TrackPicker.Next(new List<string> { "a", "a", "a" }, "a", random), "copies of one track still play");
+            ModAssert.Equal("a", TrackPicker.Next(new List<string> { "a" }, "a", random), "a single track repeats");
+            ModAssert.Null(TrackPicker.Next(new List<string>(), "a", random), "an empty bucket gives nothing");
+        }
+    }
+}