+ Added some + and - operator tests

+ Adjusted behavior so that using + or - repeatedly adds to the same Union/Difference object instead of a nasty nested chain

OSCADSharp/OSCADSharp.ConsoleTests/Program.cs

@@ -13,17 +13,19 @@ namespace OSCADSharp.ConsoleTests
     {
         static void Main(string[] args)
         {
-            var obj = new Cube(5, 10, 20).Mirror(0, 0, 1).Mirror(0, 1, 0)
+            //var obj = new Cube(5, 10, 20).Mirror(0, 0, 1).Mirror(0, 1, 0)
-                .Rotate(15, -45, 120).Translate(-20, 10, 15).Rotate(90, 15, 25)
+            //    .Rotate(15, -45, 120).Translate(-20, 10, 15).Rotate(90, 15, 25)
-                .Translate(-10, -20, -20).Rotate(-90, -90, -45);
+            //    .Translate(-10, -20, -20).Rotate(-90, -90, -45);
 
-            var pos = obj.Position();
+            var obj = new Cube() + new Sphere() + new Sphere().Translate(2, 2, 2) - new Cylinder(2, 5) + new Text3D("Hey hey!");
-            var cyl1 = new Cylinder(1, 100, true).Translate(pos);
-            var cyl2 = new Cylinder(1, 100, true).Rotate(0, 90, 0).Translate(pos);
-            var cyl3 = new Cylinder(1, 100, true).Rotate(90, 0, 0).Translate(pos);
-            var axisHelper = cyl1.Union(cyl2, cyl3).Color("Red");
 
-            string script = obj.Union(axisHelper).ToString();
+            //var pos = obj.Position();
+            //var cyl1 = new Cylinder(1, 100, true).Translate(pos);
+            //var cyl2 = new Cylinder(1, 100, true).Rotate(0, 90, 0).Translate(pos);
+            //var cyl3 = new Cylinder(1, 100, true).Rotate(90, 0, 0).Translate(pos);
+            //var axisHelper = cyl1.Union(cyl2, cyl3).Color("Red");
+
+            string script = obj.ToString(); //obj.Union(axisHelper).ToString();
 
             File.WriteAllLines("test.scad", new string[] { script.ToString() });
             //Console.ReadKey();

OSCADSharp/OSCADSharp.UnitTests/DifferenceTests.cs

@@ -1,6 +1,7 @@
 using System;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using OSCADSharp.Solids;
+using System.Linq;
 
 namespace OSCADSharp.UnitTests
 {
@@ -15,5 +16,25 @@ namespace OSCADSharp.UnitTests
 
             var pos = diff.Position();
         }
+
+        [TestMethod]
+        public void Difference_MinusOperatorCreatesDifferenceObject()
+        {
+            var obj = new Cube() - new Sphere();
+            var diff = new Sphere().Difference(new Cube());
+
+            Assert.IsTrue(obj.GetType() == diff.GetType());
+        }
+
+        [TestMethod]
+        public void Difference_ChainingMinusOperationAddsToTheSameDifferenceObject()
+        {
+            var obj = new Cube() - new Sphere() - new Text3D("WOW!") - new Cylinder().Translate(1, 2, 5);
+            var diff = new Sphere().Difference(new Cube());
+
+            var childrenThatAreDiffs = obj.Children().Where(child => child.GetType() == diff.GetType()).Count();
+
+            Assert.AreEqual(0, childrenThatAreDiffs);
+        }
     }
 }

OSCADSharp/OSCADSharp.UnitTests/UnionTests.cs

@@ -48,5 +48,25 @@ namespace OSCADSharp.UnitTests
 
             Assert.IsTrue(script.IndexOf("cube(") < script.IndexOf("cylinder("));
         }
+
+        [TestMethod]
+        public void Union_AddingObjectsCreatesUnion()
+        {
+            var obj = new Cube() + new Cylinder();
+            var union = new Cube().Union(new Cylinder());
+
+            Assert.IsTrue(obj.GetType() == union.GetType());
+        }
+
+        [TestMethod]
+        public void Union_ChainingAdditionAddsToTheSameUnion()
+        {
+            var obj = new Cube() + new Sphere() + new Text3D("WOW!") + new Cylinder().Translate(1, 2, 5);
+            var union = new Sphere().Union(new Cube());
+
+            var unionChildrenCount = obj.Children().Where(child => child.GetType() == union.GetType()).Count();
+
+            Assert.AreEqual(0, unionChildrenCount);
+        }
     }
 }

OSCADSharp/OSCADSharp/OSCADObject.cs

@@ -307,7 +307,20 @@ namespace OSCADSharp
         /// <returns></returns>
         public static OSCADObject operator +(OSCADObject left, OSCADObject right)
         {
-            return new Union(new OSCADObject[] {left, right });
+            if(left.GetType() == typeof(Union))
+            {
+                left.children.Add(right);
+                return left;
+            }
+            else if(right.GetType() == typeof(Union))
+            {
+                right.children.Add(left);
+                return right;
+            }
+            else
+            {
+                return new Union(new OSCADObject[] {left, right });
+            }
         }
 
         /// <summary>
@@ -318,7 +331,20 @@ namespace OSCADSharp
         /// <returns></returns>
         public static OSCADObject operator -(OSCADObject left, OSCADObject right)
         {
-            return new Difference(new OSCADObject[] {left, right });
+            if (left.GetType() == typeof(Difference))
+            {
+                left.children.Add(right);
+                return left;
+            }
+            else if (right.GetType() == typeof(Difference))
+            {
+                right.children.Add(left);
+                return right;
+            }
+            else
+            {
+                return new Difference(new OSCADObject[] {left, right });
+            }
         }
         #endregion
     }