refactor: tests passing again

Author: maurei

src/JsonApiDotNetCore/Data/DefaultEntityRepository.cs

@@ -242,6 +242,7 @@ public virtual async Task<TEntity> UpdateAsync(TId id, TEntity entity)
                     }
                     else if (relationshipEntry.Key is HasOneAttribute hasOneAttribute)
                     {
+                        //var foreignkeyValue = relationshipValue.GetType().GetProperty(hasOneAttribute.IdentifiablePropertyName).GetValue(oldEntity);
                         hasOneAttribute.SetValue(oldEntity, relationshipValue);
                     }
                 }
@@ -405,7 +406,7 @@ private void AttachHasManyAndHasManyThroughPointers(TEntity entity)
                     var tracked = AttachOrGetTracked(pointer);
                     if (tracked != null) alreadyTracked = true;
                     return tracked ?? pointer;
-                });
+                }).Cast(attribute.Type);
 
                 if (alreadyTracked) relationships[attribute] = (IList)newPointerCollection;
             }

src/JsonApiDotNetCore/Extensions/TypeExtensions.cs

@@ -8,6 +8,13 @@ namespace JsonApiDotNetCore.Extensions
 {
     internal static class TypeExtensions
     {
+        public static IEnumerable Cast(this IEnumerable source, Type type)
+        {
+            if (source == null) throw new ArgumentNullException(nameof(source));
+            if (type == null) throw new ArgumentNullException(nameof(type));
+            return TypeHelper.ConvertCollection(source.Cast<object>(), type);
+        }
+
         public static Type GetElementType(this IEnumerable enumerable)
         {
             var enumerableTypes = enumerable.GetType()

src/JsonApiDotNetCore/Serialization/JsonApiDeSerializer.cs

@@ -250,7 +250,7 @@ private void SetHasOneForeignKeyValue(object entity, HasOneAttribute hasOneAttr,
 
                 var convertedValue = TypeHelper.ConvertType(foreignKeyPropertyValue, foreignKeyProperty.PropertyType);
                 foreignKeyProperty.SetValue(entity, convertedValue);
-                //_jsonApiContext.RelationshipsToUpdate[hasOneAttr] = convertedValue;
+                if (convertedValue == null )  _jsonApiContext.HasOneRelationshipPointers.Add(hasOneAttr, null); 
             }
         }