Content update for NetEntities (#18935)

Content.IntegrationTests/Pair/TestPair.Helpers.cs

@@ -1,6 +1,8 @@
 #nullable enable
 using System.Linq;
+using Robust.Shared.GameObjects;
 using Robust.Shared.Map;
+using Robust.UnitTesting;
 
 namespace Content.IntegrationTests.Pair;
 
@@ -16,6 +18,7 @@ public sealed partial class TestPair
         var tileDefinitionManager = Server.ResolveDependency<ITileDefinitionManager>();
 
         var mapData = new TestMapData();
+        TestMap = mapData;
         await Server.WaitPost(() =>
         {
             mapData.MapId = Server.MapMan.CreateMap();
@@ -29,11 +32,48 @@ public sealed partial class TestPair
             mapData.MapCoords = new MapCoordinates(0, 0, mapData.MapId);
             mapData.Tile = mapData.MapGrid.GetAllTiles().First();
         });
-        
-        if (Settings.Connected)
-            await RunTicksSync(10);
 
-        TestMap = mapData;
+        if (!Settings.Connected)
+            return mapData;
+
+        await RunTicksSync(10);
+        mapData.CMapUid = ToClientUid(mapData.MapUid);
+        mapData.CGridUid = ToClientUid(mapData.GridUid);
+        mapData.CGridCoords = new EntityCoordinates(mapData.CGridUid, 0, 0);
+
         return mapData;
     }
-}
+
+    /// <summary>
+    /// Convert a client-side uid into a server-side uid
+    /// </summary>
+    public EntityUid ToServerUid(EntityUid uid) => ConvertUid(uid, Client, Server);
+
+    /// <summary>
+    /// Convert a server-side uid into a client-side uid
+    /// </summary>
+    public EntityUid ToClientUid(EntityUid uid) => ConvertUid(uid, Server, Client);
+
+    private static EntityUid ConvertUid(
+        EntityUid uid,
+        RobustIntegrationTest.IntegrationInstance source,
+        RobustIntegrationTest.IntegrationInstance destination)
+    {
+        if (!uid.IsValid())
+            return EntityUid.Invalid;
+
+        if (!source.EntMan.TryGetComponent<MetaDataComponent>(uid, out var meta))
+        {
+            Assert.Fail($"Failed to resolve MetaData while converting the EntityUid for entity {uid}");
+            return EntityUid.Invalid;
+        }
+
+        if (!destination.EntMan.TryGetEntity(meta.NetEntity, out var otherUid))
+        {
+            Assert.Fail($"Failed to resolve net ID while converting the EntityUid entity {source.EntMan.ToPrettyString(uid)}");
+            return EntityUid.Invalid;
+        }
+
+        return otherUid.Value;
+    }
+}