test: add Compactor safety-net tests before refactor

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest.Tests/CompactorTests.cs

@@ -0,0 +1,162 @@
+using OpenNest;
+using OpenNest.Engine.Fill;
+using OpenNest.Geometry;
+using Xunit;
+using System.Collections.Generic;
+
+namespace OpenNest.Tests
+{
+    public class CompactorTests
+    {
+        private static Drawing MakeRectDrawing(double w, double h)
+        {
+            var pgm = new OpenNest.CNC.Program();
+            pgm.Codes.Add(new OpenNest.CNC.RapidMove(new Vector(0, 0)));
+            pgm.Codes.Add(new OpenNest.CNC.LinearMove(new Vector(w, 0)));
+            pgm.Codes.Add(new OpenNest.CNC.LinearMove(new Vector(w, h)));
+            pgm.Codes.Add(new OpenNest.CNC.LinearMove(new Vector(0, h)));
+            pgm.Codes.Add(new OpenNest.CNC.LinearMove(new Vector(0, 0)));
+            return new Drawing("rect", pgm);
+        }
+
+        private static Part MakeRectPart(double x, double y, double w, double h)
+        {
+            var drawing = MakeRectDrawing(w, h);
+            var part = new Part(drawing) { Location = new Vector(x, y) };
+            part.UpdateBounds();
+            return part;
+        }
+
+        [Fact]
+        public void Push_Left_MovesPartTowardEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(50, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            var distance = Compactor.Push(moving, obstacles, workArea, 0, PushDirection.Left);
+
+            Assert.True(distance > 0);
+            Assert.True(part.BoundingBox.Left < 1);
+        }
+
+        [Fact]
+        public void Push_Left_StopsAtObstacle()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var obstacle = MakeRectPart(0, 0, 10, 10);
+            var part = MakeRectPart(50, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part> { obstacle };
+
+            Compactor.Push(moving, obstacles, workArea, 0, PushDirection.Left);
+
+            Assert.True(part.BoundingBox.Left >= obstacle.BoundingBox.Right - 0.1);
+        }
+
+        [Fact]
+        public void Push_Down_MovesPartTowardEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(0, 50, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            var distance = Compactor.Push(moving, obstacles, workArea, 0, PushDirection.Down);
+
+            Assert.True(distance > 0);
+            Assert.True(part.BoundingBox.Bottom < 1);
+        }
+
+        [Fact]
+        public void Push_ReturnsZero_WhenAlreadyAtEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(0, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            var distance = Compactor.Push(moving, obstacles, workArea, 0, PushDirection.Left);
+
+            Assert.Equal(0, distance);
+        }
+
+        [Fact]
+        public void Push_WithSpacing_MovesLessThanWithout()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+
+            // Push without spacing.
+            var obstacle1 = MakeRectPart(0, 0, 10, 10);
+            var part1 = MakeRectPart(50, 0, 10, 10);
+            var distNoSpacing = Compactor.Push(new List<Part> { part1 }, new List<Part> { obstacle1 }, workArea, 0, PushDirection.Left);
+
+            // Push with spacing.
+            var obstacle2 = MakeRectPart(0, 0, 10, 10);
+            var part2 = MakeRectPart(50, 0, 10, 10);
+            var distWithSpacing = Compactor.Push(new List<Part> { part2 }, new List<Part> { obstacle2 }, workArea, 2, PushDirection.Left);
+
+            // Spacing should cause the part to stop at a different position than without spacing.
+            Assert.NotEqual(distNoSpacing, distWithSpacing);
+        }
+
+        [Fact]
+        public void Push_AngleLeft_MovesPartTowardEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(50, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            // angle = π = push left
+            var distance = Compactor.Push(moving, obstacles, workArea, 0, System.Math.PI);
+
+            Assert.True(distance > 0);
+            Assert.True(part.BoundingBox.Left < 1);
+        }
+
+        [Fact]
+        public void Push_AngleDown_MovesPartTowardEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(0, 50, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            // angle = 3π/2 = push down
+            var distance = Compactor.Push(moving, obstacles, workArea, 0, 3 * System.Math.PI / 2);
+
+            Assert.True(distance > 0);
+            Assert.True(part.BoundingBox.Bottom < 1);
+        }
+
+        [Fact]
+        public void PushBoundingBox_Left_MovesPartTowardEdge()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var part = MakeRectPart(50, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part>();
+
+            var distance = Compactor.PushBoundingBox(moving, obstacles, workArea, 0, PushDirection.Left);
+
+            Assert.True(distance > 0);
+            Assert.True(part.BoundingBox.Left < 1);
+        }
+
+        [Fact]
+        public void PushBoundingBox_StopsAtObstacle()
+        {
+            var workArea = new Box(0, 0, 100, 100);
+            var obstacle = MakeRectPart(0, 0, 10, 10);
+            var part = MakeRectPart(50, 0, 10, 10);
+            var moving = new List<Part> { part };
+            var obstacles = new List<Part> { obstacle };
+
+            Compactor.PushBoundingBox(moving, obstacles, workArea, 0, PushDirection.Left);
+
+            Assert.True(part.BoundingBox.Left >= obstacle.BoundingBox.Right - 0.1);
+        }
+    }
+}