diff --git a/OpenNest.Tests/Geometry/SpatialQueryTests.cs b/OpenNest.Tests/Geometry/SpatialQueryTests.cs
new file mode 100644
index 0000000..dd99fb4
--- /dev/null
+++ b/OpenNest.Tests/Geometry/SpatialQueryTests.cs
@@ -0,0 +1,349 @@
+using OpenNest.Geometry;
+using OpenNest.Math;
+using System.Collections.Generic;
+
+namespace OpenNest.Tests.Geometry;
+
+public class SpatialQueryTests
+{
+    #region Helpers
+
+    private static List<Entity> MakeSquare(double size)
+    {
+        return new List<Entity>
+        {
+            new Line(0, 0, size, 0),
+            new Line(size, 0, size, size),
+            new Line(size, size, 0, size),
+            new Line(0, size, 0, 0),
+        };
+    }
+
+    private static List<Entity> MakeRoundedRect(double length, double width, double r)
+    {
+        return new List<Entity>
+        {
+            new Line(r, 0, length - r, 0),
+            new Arc(length - r, r, r, Angle.ToRadians(270), Angle.ToRadians(360)),
+            new Line(length, r, length, width - r),
+            new Arc(length - r, width - r, r, Angle.ToRadians(0), Angle.ToRadians(90)),
+            new Line(length - r, width, r, width),
+            new Arc(r, width - r, r, Angle.ToRadians(90), Angle.ToRadians(180)),
+            new Line(0, width - r, 0, r),
+            new Arc(r, r, r, Angle.ToRadians(180), Angle.ToRadians(270)),
+        };
+    }
+
+    private static List<Entity> MakeCircle(double cx, double cy, double radius)
+    {
+        return new List<Entity> { new Circle(cx, cy, radius) };
+    }
+
+    private static List<Entity> Translate(List<Entity> entities, double dx, double dy)
+    {
+        var result = new List<Entity>();
+        foreach (var e in entities)
+        {
+            if (e is Line line)
+                result.Add(new Line(line.pt1.X + dx, line.pt1.Y + dy, line.pt2.X + dx, line.pt2.Y + dy));
+            else if (e is Arc arc)
+                result.Add(new Arc(arc.Center.X + dx, arc.Center.Y + dy, arc.Radius, arc.StartAngle, arc.EndAngle));
+            else if (e is Circle circle)
+                result.Add(new Circle(circle.Center.X + dx, circle.Center.Y + dy, circle.Radius));
+        }
+        return result;
+    }
+
+    #endregion
+
+    #region Circle vs Circle
+
+    [Fact]
+    public void CircleToCircle_Right_ReturnsGap()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Left_ReturnsGap()
+    {
+        var a = MakeCircle(20, 0, 5);
+        var b = MakeCircle(0, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(-1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Up_ReturnsGap()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(0, 20, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, 1));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Touching_ReturnsZero()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(10, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void CircleToCircle_NoPath_ReturnsMaxValue()
+    {
+        var a = MakeCircle(0, 0, 3);
+        var b = MakeCircle(0, 20, 3);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void CircleToCircle_PushDirection_Right()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, PushDirection.Right);
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Square vs Square
+
+    [Fact]
+    public void SquareToSquare_Right_ReturnsGap()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 25, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Left_ReturnsGap()
+    {
+        var a = Translate(MakeSquare(10), 25, 0);
+        var b = MakeSquare(10);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(-1, 0));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Down_ReturnsGap()
+    {
+        var a = Translate(MakeSquare(10), 0, 25);
+        var b = MakeSquare(10);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, -1));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Touching_ReturnsZero()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 10, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void SquareToSquare_NoOverlap_ReturnsMaxValue()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 0, 20);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void SquareToSquare_PartialOverlap_Right()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 20, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Rounded Rectangle
+
+    [Fact]
+    public void RoundedRect_Right_ReturnsGap()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 30, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void RoundedRect_Up_ReturnsGap()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 0, 25);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, 1));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void RoundedRect_Touching_ReturnsZero()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 20, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void RoundedRect_Diagonal_ReturnsDistance()
+    {
+        var dir = new Vector(1 / System.Math.Sqrt(2), 1 / System.Math.Sqrt(2));
+        var a = MakeRoundedRect(10, 10, 2);
+        var b = Translate(MakeRoundedRect(10, 10, 2), 20, 20);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, dir);
+
+        Assert.True(dist > 0 && dist < double.MaxValue);
+    }
+
+    #endregion
+
+    #region Circle vs Square
+
+    [Fact]
+    public void CircleToSquare_Right_ReturnsGap()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var square = Translate(MakeSquare(10), 15, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, square, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void SquareToCircle_Right_ReturnsGap()
+    {
+        var square = MakeSquare(10);
+        var circle = MakeCircle(25, 5, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(square, circle, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToSquare_Touching_ReturnsZero()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var square = Translate(MakeSquare(10), 5, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, square, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    #endregion
+
+    #region Circle vs Rounded Rectangle
+
+    [Fact]
+    public void CircleToRoundedRect_Right_ReturnsGap()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var rect = Translate(MakeRoundedRect(20, 10, 2), 15, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, rect, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void RoundedRectToCircle_Left_ReturnsGap()
+    {
+        var rect = Translate(MakeRoundedRect(20, 10, 2), 15, 0);
+        var circle = MakeCircle(0, 5, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(rect, circle, new Vector(-1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Edge cases
+
+    [Fact]
+    public void EmptyLists_ReturnsMaxValue()
+    {
+        var a = new List<Entity>();
+        var b = new List<Entity>();
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void Symmetry_LeftRightReturnSameDistance()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 25, 0);
+
+        var right = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+        var left = SpatialQuery.DirectionalDistance(b, a, new Vector(-1, 0));
+
+        Assert.InRange(System.Math.Abs(right - left), 0, 0.01);
+    }
+
+    [Fact]
+    public void Symmetry_CirclesLeftRightSame()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var right = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+        var left = SpatialQuery.DirectionalDistance(b, a, new Vector(-1, 0));
+
+        Assert.InRange(System.Math.Abs(right - left), 0, 0.01);
+    }
+
+    #endregion
+}