Export variant's display_name if present

The `#name` method is simply delegated to a variant's product.

engines/dfc_provider/app/services/dfc_builder.rb

@@ -22,8 +22,10 @@ class DfcBuilder
     )
 
     DataFoodConsortium::Connector::SuppliedProduct.new(
-      id, name: variant.name, description: variant.description,
-          quantity: QuantitativeValueBuilder.quantity(variant),
+      id,
+      name: variant.name_to_display,
+      description: variant.description,
+      quantity: QuantitativeValueBuilder.quantity(variant),
     )
   end
 

engines/dfc_provider/spec/services/supplied_product_builder_spec.rb

@@ -22,5 +22,20 @@ describe DfcBuilder do
       expect(product.quantity.value).to eq 1.0
       expect(product.quantity.unit.semanticId).to eq "dfc-m:Gram"
     end
+
+    it "assigns the product name by default" do
+      variant.product.name = "Apple"
+      product = DfcBuilder.supplied_product(variant)
+
+      expect(product.name).to eq "Apple"
+    end
+
+    it "assigns the variant name if present" do
+      variant.product.name = "Apple"
+      variant.display_name = "Granny Smith"
+      product = DfcBuilder.supplied_product(variant)
+
+      expect(product.name).to eq "Granny Smith"
+    end
   end
 end