Redirect user to cart page if some item in the order is unavailable

app/controllers/checkout_controller.rb

@@ -169,7 +169,7 @@ class CheckoutController < Spree::CheckoutController
   def load_order
     @order = current_order
     redirect_to main_app.shop_path and return unless @order and @order.checkout_allowed?
-    raise_insufficient_quantity and return if @order.insufficient_stock_lines.present?
+    redirect_to_cart_path and return unless valid_order_line_items?
     redirect_to main_app.shop_path and return if @order.completed?
     before_address
     setup_for_current_state
@@ -184,8 +184,11 @@ class CheckoutController < Spree::CheckoutController
     @order.ship_address = finder.ship_address
   end
 
-  # Overriding Spree's methods
-  def raise_insufficient_quantity
+  def valid_order_line_items?
+    @order.insufficient_stock_lines.empty? && OrderCycleDistributedVariants.new(@order.order_cycle, @order.distributor).distributes_order_variants?(@order)
+  end
+
+  def redirect_to_cart_path
     respond_to do |format|
       format.html do
         redirect_to cart_path

spec/controllers/checkout_controller_spec.rb

@@ -36,22 +36,40 @@ describe CheckoutController, type: :controller do
     flash[:info].should == "The hub you have selected is temporarily closed for orders. Please try again later."
   end
 
-  it "redirects to the cart when some items are out of stock" do
-    controller.stub(:current_distributor).and_return(distributor)
-    controller.stub(:current_order_cycle).and_return(order_cycle)
-    controller.stub(:current_order).and_return(order)
-    order.stub_chain(:insufficient_stock_lines, :present?).and_return true
-    get :edit
-    response.should redirect_to spree.cart_path
-  end
+  describe "redirection to the cart" do
+    let(:order_cycle_distributed_variants) { double(:order_cycle_distributed_variants) }
 
-  it "renders when both distributor and order cycle is selected" do
-    controller.stub(:current_distributor).and_return(distributor)
-    controller.stub(:current_order_cycle).and_return(order_cycle)
-    controller.stub(:current_order).and_return(order)
-    order.stub_chain(:insufficient_stock_lines, :present?).and_return false
-    get :edit
-    response.should be_success
+    before do
+      controller.stub(:current_order).and_return(order)
+      order.stub(:distributor).and_return(distributor)
+      order.order_cycle = order_cycle
+
+      allow(OrderCycleDistributedVariants).to receive(:new).with(order_cycle, distributor).and_return(order_cycle_distributed_variants)      
+    end
+
+    it "redirects when some items are out of stock" do
+      allow(order).to receive_message_chain(:insufficient_stock_lines, :empty?).and_return false
+
+      get :edit
+      expect(response).to redirect_to spree.cart_path
+    end
+
+    it "redirects when some items are not available" do
+      allow(order).to receive_message_chain(:insufficient_stock_lines, :empty?).and_return true
+      expect(order_cycle_distributed_variants).to receive(:distributes_order_variants?).with(order).and_return(false)
+
+      get :edit
+      expect(response).to redirect_to spree.cart_path
+    end
+
+
+    it "does not redirect when items are available and in stock" do
+      allow(order).to receive_message_chain(:insufficient_stock_lines, :empty?).and_return true
+      expect(order_cycle_distributed_variants).to receive(:distributes_order_variants?).with(order).and_return(true)
+
+      get :edit
+      expect(response).to be_success
+    end
   end
 
   describe "building the order" do

spec/requests/checkout/failed_checkout_spec.rb

@@ -23,6 +23,10 @@ describe "checking out an order that initially fails", type: :request do
   end
 
   before do
+    order_cycle_distributed_variants = double(:order_cycle_distributed_variants)
+    allow(OrderCycleDistributedVariants).to receive(:new).and_return(order_cycle_distributed_variants)
+    allow(order_cycle_distributed_variants).to receive(:distributes_order_variants?).and_return(true)
+
     order.reload.update_totals
     set_order order
   end

spec/requests/checkout/stripe_connect_spec.rb

@@ -27,6 +27,10 @@ describe "checking out an order with a Stripe Connect payment method", type: :re
   end
 
   before do
+    order_cycle_distributed_variants = double(:order_cycle_distributed_variants)
+    allow(OrderCycleDistributedVariants).to receive(:new).and_return(order_cycle_distributed_variants)
+    allow(order_cycle_distributed_variants).to receive(:distributes_order_variants?).and_return(true)
+
     allow(Stripe).to receive(:api_key) { "sk_test_12345" }
     order.update_attributes(distributor_id: enterprise.id, order_cycle_id: order_cycle.id)
     order.reload.update_totals