Added the Model Comparison assistant for blind comparisons of two models (#1009)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/Tests/Assistants/ModelComparison/ModelComparisonPresetChoiceTests.cs

@@ -0,0 +1,55 @@
+using AIStudio.Assistants.ModelComparison;
+using AIStudio.Settings.DataModel;
+
+namespace AIStudio.Tests.Assistants.ModelComparison;
+
+/// <summary>
+/// Checks which preset the Answer Test of the Model Comparison assistant opens with.
+/// </summary>
+[TestFixture]
+public sealed class ModelComparisonPresetChoiceTests
+{
+    private static readonly ModelComparisonPreset FIRST = new() { Id = Guid.Parse("11111111-1111-1111-1111-111111111111"), Name = "Alpha" };
+    private static readonly ModelComparisonPreset SECOND = new() { Id = Guid.Parse("22222222-2222-2222-2222-222222222222"), Name = "Beta" };
+
+    [Test]
+    public void ThePreselectedPresetComesFirst()
+    {
+        var options = new DataModelComparison { PreselectOptions = true, PreselectedPresetId = SECOND.Id.ToString("D") };
+
+        Assert.That(ModelComparisonPresetChoice.Choose([FIRST, SECOND], options), Is.EqualTo(SECOND.Id));
+    }
+
+    [Test]
+    public void WithoutOptionsThePreselectedPresetDoesNotCount()
+    {
+        var options = new DataModelComparison { PreselectOptions = false, PreselectedPresetId = SECOND.Id.ToString("D") };
+
+        Assert.That(ModelComparisonPresetChoice.Choose([FIRST, SECOND], options), Is.EqualTo(FIRST.Id), "With the options switched off, the stored preset must not count.");
+    }
+
+    [Test]
+    public void ADeletedPreselectedPresetFallsBackToTheFirstOne()
+    {
+        var options = new DataModelComparison { PreselectOptions = true, PreselectedPresetId = "33333333-3333-3333-3333-333333333333" };
+
+        Assert.That(ModelComparisonPresetChoice.Choose([FIRST, SECOND], options), Is.EqualTo(FIRST.Id));
+    }
+
+    [Test]
+    public void ThePresetIdCountsWhateverItsCase()
+    {
+        var options = new DataModelComparison { PreselectOptions = true, PreselectedPresetId = "BBBBBBBB-2222-2222-2222-222222222222" };
+        var preset = new ModelComparisonPreset { Id = Guid.Parse("bbbbbbbb-2222-2222-2222-222222222222"), Name = "Gamma" };
+
+        Assert.That(ModelComparisonPresetChoice.Choose([FIRST, preset], options), Is.EqualTo(preset.Id));
+    }
+
+    [Test]
+    public void WithoutPresetsANewOneIsNeeded()
+    {
+        var options = new DataModelComparison { PreselectOptions = true, PreselectedPresetId = SECOND.Id.ToString("D") };
+
+        Assert.That(ModelComparisonPresetChoice.Choose([], options), Is.Null);
+    }
+}