Moved tests from Gateway to Sia-Root submodule for

shared components

Domain/Sia.Shared/Data/PartialJsonResolver.cs

@@ -25,7 +25,7 @@ namespace Sia.Shared.Data
         where TDestination: IJsonDataString
     {
         public string Resolve(TSource source, TDestination destination, string destMember, ResolutionContext context)
-            => source.Data is null ? null : JsonConvert.SerializeObject(source.Data);
+            => source?.Data is null ? null : JsonConvert.SerializeObject(source.Data);
     }
 
     public class ResolveStringToJson<TSource, TDestination>
@@ -34,6 +34,6 @@ namespace Sia.Shared.Data
         where TDestination : IJsonDataObject
     {
         public object Resolve(TSource source, TDestination destination, object destMember, ResolutionContext context)
-            => source.Data is null ? null : JsonConvert.DeserializeObject(source.Data);
+            => source?.Data is null ? null : JsonConvert.DeserializeObject(source.Data);
     }
 }