We no longer verify CannotRemoveZeroQuantityItem constraint

It is removed from Ordering as it is one of rare needs to keep items in there. We want to move some of the logic to Pricing later on.

ecommerce/ordering/lib/ordering/order.rb

@@ -7,7 +7,6 @@ class Order
     AlreadyConfirmed = Class.new(InvalidState)
     NotSubmitted = Class.new(InvalidState)
     OrderHasExpired = Class.new(InvalidState)
-    CannotRemoveZeroQuantityItem = Class.new(StandardError)
 
     def initialize(id)
       @id = id
@@ -70,7 +69,6 @@ def add_item(product_id)
 
     def remove_item(product_id)
       raise AlreadySubmitted unless @state.equal?(:draft)
-      raise CannotRemoveZeroQuantityItem if @basket.quantity(product_id).zero?
       apply ItemRemovedFromBasket.new(data: { order_id: @id, product_id: product_id })
     end
 

ecommerce/ordering/test/remove_item_from_basket_test.rb

@@ -49,14 +49,5 @@ def test_no_remove_allowed_to_created_order
         act(RemoveItemFromBasket.new(order_id: aggregate_id, product_id: product_id))
       end
     end
-
-    def test_no_remove_allowed_if_item_quantity_eq_zero
-      aggregate_id = SecureRandom.uuid
-      product_id = SecureRandom.uuid
-
-      assert_raises(Order::CannotRemoveZeroQuantityItem) do
-        act(RemoveItemFromBasket.new(order_id: aggregate_id, product_id: product_id))
-      end
-    end
   end
 end

rails_application/app/controllers/client/orders_controller.rb

@@ -55,9 +55,6 @@ def remove_item
           product_id: params[:product_id]
         )
       )
-    rescue Ordering::Order::CannotRemoveZeroQuantityItem
-      redirect_to edit_client_order_path(params[:id]),
-                  alert: "Cannot remove the product with 0 quantity"
     end
 
   end

rails_application/app/controllers/orders_controller.rb

@@ -68,8 +68,6 @@ def add_item
   def remove_item
     command_bus.(Ordering::RemoveItemFromBasket.new(order_id: params[:id], product_id: params[:product_id]))
     head :ok
-  rescue Ordering::Order::CannotRemoveZeroQuantityItem
-    redirect_to edit_order_path(params[:id]), alert: "Cannot remove the product with 0 quantity"
   end
 
   def create