Override default spree splitters config (was Shipping Category and Backordered) to use only Base splitter, this splitter does not split the orders into multiple shipments

In OFN we cannot split the orders because one order can only have one shipment

Additionally, add spec to validate that the order workflow now works with products with different shipping categories

config/application.rb

@@ -83,6 +83,17 @@ module Openfoodnetwork
       ]
     end
 
+    # Every splitter (except Base splitter) will split the order in multiple packages
+    #   Each package will generate a separate shipment in the order
+    #   Base splitter does not split the packages
+    #   So, because in OFN we have locked orders to have only one shipment,
+    #     we must use this splitter and no other
+    initializer "spree.register.stock_splitters" do |app|
+      app.config.spree.stock_splitters = [
+        Spree::Stock::Splitter::Base
+      ]
+    end
+
     # Register Spree payment methods
     initializer "spree.gateway.payment_methods", :after => "spree.register.payment_methods" do |app|
       app.config.spree.payment_methods << Spree::Gateway::Migs

spec/config/application_spec.rb

@@ -0,0 +1,9 @@
+require 'spec_helper'
+
+describe Openfoodnetwork::Application, 'configuration' do
+  let(:config) { described_class.config }
+
+  it "sets Spree::Stock::Splitter::Base as the only stock splitter" do
+    expect(config.spree.stock_splitters).to eq [Spree::Stock::Splitter::Base]
+  end
+end

spec/models/spree/order/checkout_spec.rb

@@ -2,9 +2,9 @@ require 'spec_helper'
 
 describe Spree::Order do
   describe 'event :restart_checkout' do
-    context 'when the order is not complete' do
-      let(:order) { create(:order) }
+    let(:order) { create(:order) }
 
+    context 'when the order is not complete' do
       before { allow(order).to receive(:completed?) { false } }
 
       it 'does transition to cart state' do
@@ -13,8 +13,6 @@ describe Spree::Order do
     end
 
     context 'when the order is complete' do
-      let(:order) { create(:order) }
-
       before { allow(order).to receive(:completed?) { true } }
 
       it 'raises' do
@@ -26,4 +24,32 @@ describe Spree::Order do
       end
     end
   end
+
+  describe "order with products with different shipping categories" do
+    let(:order) { create(:order_with_totals_and_distribution, ship_address: create(:address) ) }
+    let(:shipping_method) { create(:shipping_method, distributors: [order.distributor]) }
+    let(:other_shipping_category) { create(:shipping_category) }
+    let(:other_product) { create(:product, shipping_category: other_shipping_category ) }
+    let(:other_variant) { other_product.variants.first }
+
+    before do
+      order.order_cycle = create(:simple_order_cycle,
+                                 distributors: [order.distributor],
+                                 variants: [order.line_items.first.variant, other_variant])
+      order.line_items = [order.line_items.first, create(:line_item,
+                                                         order: order,
+                                                         variant: other_variant)]
+    end
+
+    it "can progress to delivery" do
+      shipping_method.shipping_categories << other_shipping_category
+
+      # If the shipping category package splitter is enabled,
+      #   an order with products with two shipping categories will be split into two shipments
+      #   and the spec will fail with a unique constraint error on index_spree_shipments_on_order_id
+      order.next
+      order.next
+      expect(order.state).to eq "delivery"
+    end
+  end
 end