From e0878096f455d117f3397c6637ea685c12923c6e Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Tue, 27 Dec 2022 14:33:04 +1100
Subject: [PATCH] Add AttachToGridOrMap test (#3625)

Closes https://github.com/space-wizards/RobustToolbox/issues/3624
---
 .../GameObjects/TransformComponent_Tests.cs   | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Robust.UnitTesting/Shared/GameObjects/TransformComponent_Tests.cs b/Robust.UnitTesting/Shared/GameObjects/TransformComponent_Tests.cs
index 9dfa14c8a..3ea2c3d20 100644
--- a/Robust.UnitTesting/Shared/GameObjects/TransformComponent_Tests.cs
+++ b/Robust.UnitTesting/Shared/GameObjects/TransformComponent_Tests.cs
@@ -43,5 +43,32 @@ namespace Robust.UnitTesting.Shared.GameObjects
 
             Assert.That(invWorldMatrix, Is.EqualTo(xform2.InvWorldMatrix));
         }
+
+        /// <summary>
+        /// Asserts that when AttachToGridOrMap is called the entity remains in the same position.
+        /// </summary>
+        [Test]
+        public void AttachToGridOrMap()
+        {
+            var server = RobustServerSimulation.NewSimulation().InitializeInstance();
+
+            var entManager = server.Resolve<IEntityManager>();
+            var mapManager = server.Resolve<IMapManager>();
+
+            var mapId = mapManager.CreateMap();
+            var grid = mapManager.CreateGrid(mapId);
+            grid.SetTile(new Vector2i(0, 0), new Tile(1));
+            var gridXform = entManager.GetComponent<TransformComponent>(grid.Owner);
+            gridXform.LocalPosition = new Vector2(0f, 100f);
+
+            var ent1 = entManager.SpawnEntity(null, new EntityCoordinates(grid.Owner, Vector2.One * grid.TileSize / 2));
+            var ent2 = entManager.SpawnEntity(null, new EntityCoordinates(ent1, Vector2.Zero));
+
+            var xform2 = entManager.GetComponent<TransformComponent>(ent2);
+            Assert.That(xform2.WorldPosition, Is.EqualTo(new Vector2(0.5f, 100.5f)));
+
+            xform2.AttachToGridOrMap();
+            Assert.That(xform2.LocalPosition, Is.EqualTo(Vector2.One * grid.TileSize / 2));
+        }
     }
 }