Bring shipment factory from spree_core and merge with modification

spec/factories/shipment_factory.rb

@@ -1,4 +1,25 @@
 FactoryBot.define do
+  factory :shipment, class: Spree::Shipment do
+    # keeps test shipments unique per order
+    initialize_with { Spree::Shipment.find_or_create_by(order_id: order.id) }
+
+    tracking 'U10000'
+    number '100'
+    cost 100.00
+    state 'pending'
+    order
+    address
+    stock_location
+
+    after(:create) do |shipment, evalulator|
+      shipment.add_shipping_method(create(:shipping_method), true)
+
+      shipment.order.line_items.each do |line_item|
+        line_item.quantity.times { shipment.inventory_units.create(variant_id: line_item.variant_id) }
+      end
+    end
+  end
+
   factory :shipment_with, class: Spree::Shipment do
     tracking 'U10000'
     number '100'
@@ -27,10 +48,3 @@ FactoryBot.define do
     end
   end
 end
-
-FactoryBot.modify do
-  factory :shipment, class: Spree::Shipment do
-    # keeps test shipments unique per order
-    initialize_with { Spree::Shipment.find_or_create_by(order_id: order.id) }
-  end
-end