Better error when submitting order with out of stock product

ecommerce/processes/lib/processes/reservation_process.rb

@@ -93,4 +93,4 @@ def product_reserved(product_id)
       end
     end
   end
-end
+end

rails_application/app/controllers/orders_controller.rb

@@ -75,7 +75,13 @@ def remove_item
 
   def create
     ApplicationRecord.transaction { submit_order(params[:order_id], params[:customer_id]) }
-    redirect_to order_path(params[:order_id]), notice: "Your order is being submitted"
+
+    order = Orders::Order.find_by_uid(params[:order_id])
+    if order.state == "Submitted"
+      redirect_to order_path(params[:order_id]), notice: "Your order is being submitted"
+    else
+      redirect_to edit_order_path(params[:order_id]), alert: "Order can not be submitted! Product not available in requested quantity!"
+    end
   rescue Ordering::Order::IsEmpty
     redirect_to edit_order_path(params[:order_id]), alert: "You can't submit an empty order"
   rescue Crm::Customer::NotExists

rails_application/test/integration/orders_test.rb

@@ -203,6 +203,22 @@ def test_empty_order_cannot_be_submitted
     assert_select "#alert", "You can't submit an empty order"
   end
 
+  def test_order_cannot_be_submitted_with_out_of_stock_product
+    product_id = register_product("Fearless Refactoring", 4, 10)
+    shopify_id = register_customer("Shopify")
+
+    supply_product(product_id, 1)
+    order_1_id = SecureRandom.uuid
+    order_2_id = SecureRandom.uuid
+    post "/orders/#{order_1_id}/add_item?product_id=#{product_id}"
+    post "/orders/#{order_2_id}/add_item?product_id=#{product_id}"
+
+    post "/orders", params: { order_id: order_1_id, customer_id: shopify_id }
+    post "/orders", params: { order_id: order_2_id, customer_id: shopify_id }
+
+    assert_equal "Order can not be submitted! Product not available in requested quantity!", flash[:alert]
+  end
+
   private
 
   def assert_remove_buttons_visible(async_remote_id, fearless_id, order_id)