Include product group objects in our catalog response

And when we import a catalog, we don't try to import those product
groups as Spree::Variant. We just see them as reference to
Spree::Product.

engines/dfc_provider/app/controllers/dfc_provider/catalog_items_controller.rb

@@ -19,6 +19,7 @@ module DfcProvider
         *person.affiliatedOrganizations,
         *person.affiliatedOrganizations.flat_map(&:catalogItems),
         *person.affiliatedOrganizations.flat_map(&:catalogItems).map(&:product),
+        *person.affiliatedOrganizations.flat_map(&:catalogItems).map(&:product).flat_map(&:isVariantOf),
         *person.affiliatedOrganizations.flat_map(&:catalogItems).flat_map(&:offers),
       )
     end

engines/dfc_provider/app/services/dfc_catalog.rb

@@ -13,9 +13,13 @@ class DfcCatalog
     @graph = graph
   end
 
+  # List all products in this catalog.
+  # These are SuppliedProduct objects which may be grouped as variants.
+  # But we don't return the parent products having variants.
   def products
     @products ||= @graph.select do |subject|
-      subject.is_a? DataFoodConsortium::Connector::SuppliedProduct
+      subject.is_a?(DataFoodConsortium::Connector::SuppliedProduct) &&
+        subject.variants.blank?
     end
   end
 

swagger/dfc.yaml

@@ -180,6 +180,9 @@ paths:
                       dfc-b:isVariantOf: http://test.host/api/dfc/enterprises/10000/product_groups/90000
                       ofn:spree_product_id: 90000
                       ofn:spree_product_uri: http://test.host/api/dfc/enterprises/10000?spree_product_id=90000
+                    - "@id": http://test.host/api/dfc/enterprises/10000/product_groups/90000
+                      "@type": dfc-b:SuppliedProduct
+                      dfc-b:hasVariant: http://test.host/api/dfc/enterprises/10000/supplied_products/10001
                     - "@id": http://test.host/api/dfc/enterprises/10000/offers/10001
                       "@type": dfc-b:Offer
                       dfc-b:hasPrice: