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/ModelComparisonWinShareTests.cs

@@ -0,0 +1,71 @@
+using AIStudio.Assistants.ModelComparison;
+
+namespace AIStudio.Tests.Assistants.ModelComparison;
+
+/// <summary>
+/// Checks the share of wins and its Wilson score interval, against values computed by hand.
+/// </summary>
+[TestFixture]
+public sealed class ModelComparisonWinShareTests
+{
+    private const double TOLERANCE = 0.001;
+
+    [Test]
+    public void WithoutDecidedRunsNothingIsClear()
+    {
+        var winShare = ModelComparisonWinShare.Of(0, 0);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(winShare.Share, Is.Null);
+            Assert.That(winShare.LowerBound, Is.Null);
+            Assert.That(winShare.UpperBound, Is.Null);
+            Assert.That(winShare.Significance, Is.EqualTo(ModelComparisonSignificance.NOT_YET_CLEAR));
+        }
+    }
+
+    [Test]
+    public void EightOfTenIsNotYetClear()
+    {
+        var winShare = ModelComparisonWinShare.Of(8, 2);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(winShare.Share, Is.EqualTo(0.8).Within(TOLERANCE));
+            Assert.That(winShare.LowerBound, Is.EqualTo(0.4902).Within(TOLERANCE));
+            Assert.That(winShare.UpperBound, Is.EqualTo(0.9433).Within(TOLERANCE));
+            Assert.That(winShare.Significance, Is.EqualTo(ModelComparisonSignificance.NOT_YET_CLEAR), "The interval still reaches below one half.");
+        }
+    }
+
+    [Test]
+    public void EighteenOfTwentyIsClearlyBetter()
+    {
+        var winShare = ModelComparisonWinShare.Of(18, 2);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(winShare.LowerBound, Is.EqualTo(0.6990).Within(TOLERANCE));
+            Assert.That(winShare.Significance, Is.EqualTo(ModelComparisonSignificance.CLEARLY_BETTER));
+        }
+    }
+
+    [Test]
+    public void NoneOfTenIsClearlyWorse()
+    {
+        var winShare = ModelComparisonWinShare.Of(0, 10);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(winShare.LowerBound, Is.EqualTo(0).Within(TOLERANCE));
+            Assert.That(winShare.UpperBound, Is.EqualTo(0.2775).Within(TOLERANCE));
+            Assert.That(winShare.Significance, Is.EqualTo(ModelComparisonSignificance.CLEARLY_WORSE));
+        }
+    }
+
+    [Test]
+    public void ANegativeCountIsRefused()
+    {
+        Assert.That(() => ModelComparisonWinShare.Of(-1, 3), Throws.TypeOf<ArgumentOutOfRangeException>());
+    }
+}