Initialize CBDD solution and add a .NET-focused gitignore for generated artifacts.

tests/CBDD.Tests/VectorMathTests.cs

@@ -0,0 +1,50 @@
+using ZB.MOM.WW.CBDD.Core.Indexing;
+
+namespace ZB.MOM.WW.CBDD.Tests;
+
+public class VectorMathTests
+{
+    [Fact]
+    public void Distance_Should_Cover_All_Metrics()
+    {
+        float[] v1 = [1f, 2f];
+        float[] v2 = [3f, 4f];
+
+        var cosineDistance = VectorMath.Distance(v1, v2, VectorMetric.Cosine);
+        var l2Distance = VectorMath.Distance(v1, v2, VectorMetric.L2);
+        var dotDistance = VectorMath.Distance(v1, v2, VectorMetric.DotProduct);
+
+        l2Distance.ShouldBe(8f);
+        dotDistance.ShouldBe(-11f);
+
+        var expectedCosine = 1f - (11f / (MathF.Sqrt(5f) * 5f));
+        MathF.Abs(cosineDistance - expectedCosine).ShouldBeLessThan(0.0001f);
+    }
+
+    [Fact]
+    public void CosineSimilarity_Should_Return_Zero_For_ZeroMagnitude_Vector()
+    {
+        float[] v1 = [0f, 0f, 0f];
+        float[] v2 = [1f, 2f, 3f];
+
+        VectorMath.CosineSimilarity(v1, v2).ShouldBe(0f);
+    }
+
+    [Fact]
+    public void DotProduct_Should_Throw_For_Length_Mismatch()
+    {
+        float[] v1 = [1f, 2f];
+        float[] v2 = [1f];
+
+        Should.Throw<ArgumentException>(() => VectorMath.DotProduct(v1, v2));
+    }
+
+    [Fact]
+    public void EuclideanDistanceSquared_Should_Throw_For_Length_Mismatch()
+    {
+        float[] v1 = [1f, 2f, 3f];
+        float[] v2 = [1f, 2f];
+
+        Should.Throw<ArgumentException>(() => VectorMath.EuclideanDistanceSquared(v1, v2));
+    }
+}