Adds an integration test for saving and loading a multi grid map.

Fixes a bug in SharedGalacticMarketComponent where the products were not being cleared between calls to ExposeData.

Content.IntegrationTests/Tests/SaveLoadMapTest.cs

@@ -0,0 +1,71 @@
+using System.Threading.Tasks;
+using NUnit.Framework;
+using Robust.Server.Interfaces.Maps;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Map;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+
+namespace Content.IntegrationTests.Tests
+{
+    [TestFixture]
+    class SaveLoadMapTest : ContentIntegrationTest
+    {
+        [Test]
+        public async Task SaveLoadMultiGridMap()
+        {
+            const string mapPath = @"Maps/Test/TestMap.yml";
+
+            var server = StartServer();
+            await server.WaitIdleAsync();
+            var mapLoader = server.ResolveDependency<IMapLoader>();
+            var mapManager = server.ResolveDependency<IMapManager>();
+            var entityManager = server.ResolveDependency<IEntityManager>();
+
+            server.Post(() =>
+            {
+                var mapId = mapManager.CreateMap(new MapId(5));
+
+                {
+                    var mapGrid = mapManager.CreateGrid(mapId);
+                    var mapGridEnt = entityManager.GetEntity(mapGrid.GridEntityId);
+                    mapGridEnt.Transform.WorldPosition = new Vector2(10, 10);
+                    mapGrid.SetTile(new MapIndices(0,0), new Tile(1, 512));
+                }
+                {
+                    var mapGrid = mapManager.CreateGrid(mapId);
+                    var mapGridEnt = entityManager.GetEntity(mapGrid.GridEntityId);
+                    mapGridEnt.Transform.WorldPosition = new Vector2(-8, -8);
+                    mapGrid.SetTile(new MapIndices(0, 0), new Tile(2, 511));
+                }
+
+                mapLoader.SaveMap(mapId, mapPath);
+
+                mapManager.DeleteMap(new MapId(5));
+            });
+            await server.WaitIdleAsync();
+
+            server.Post(() =>
+            {
+                mapLoader.LoadMap(new MapId(10), mapPath);
+            });
+            await server.WaitIdleAsync();
+
+            {
+                if(!mapManager.TryFindGridAt(new MapId(10), new Vector2(10,10), out var mapGrid))
+                    Assert.Fail();
+
+                Assert.AreEqual(new Vector2(10, 10), mapGrid.WorldPosition);
+                Assert.AreEqual(new Tile(1, 512), mapGrid.GetTileRef(new MapIndices(0, 0)).Tile);
+            }
+            {
+                if (!mapManager.TryFindGridAt(new MapId(10), new Vector2(-8, -8), out var mapGrid))
+                    Assert.Fail();
+
+                Assert.AreEqual(new Vector2(-8, -8), mapGrid.WorldPosition);
+                Assert.AreEqual(new Tile(2, 511), mapGrid.GetTileRef(new MapIndices(0, 0)).Tile);
+            }
+
+        }
+    }
+}

Content.Shared/GameObjects/Components/Cargo/SharedGalacticMarketComponent.cs

@@ -69,6 +69,7 @@ namespace Content.Shared.GameObjects.Components.Cargo
             {
                 var products = serializer.ReadDataField("products", new List<string>());
                 var prototypeManager = IoCManager.Resolve<IPrototypeManager>();
+                _products.Clear();
                 foreach (var id in products)
                 {
                     if (!prototypeManager.TryIndex(id, out CargoProductPrototype product))