When order distributor changes, update line item shipping method

app/models/spree/line_item_decorator.rb

@@ -5,7 +5,15 @@ Spree::LineItem.class_eval do
 
   before_create :set_itemwise_shipping_method
 
+
   def itemwise_shipping_cost
+    # When order has not yet been placed, update shipping method in case order
+    # has changed to a distributor with a different shipping method
+    if %w(cart address delivery resumed).include? self.order.state
+      set_itemwise_shipping_method
+      save! if shipping_method_id_changed?
+    end
+
     order = OpenStruct.new :line_items => [self]
     shipping_method.compute_amount(order)
   end

app/models/spree/order_decorator.rb

@@ -3,10 +3,10 @@ require 'open_food_web/distributor_change_validator'
 Spree::Order.class_eval do
   belongs_to :distributor, :class_name => 'Enterprise'
 
-  before_validation :shipping_address_from_distributor
   validate :products_available_from_new_distributor, :if => :distributor_id_changed?
   attr_accessible :distributor_id
 
+  before_validation :shipping_address_from_distributor
   after_create :set_default_shipping_method
 
   

spec/features/chili/enterprises_distributor_info_rich_text_feature_spec.rb

@@ -73,6 +73,7 @@ feature "enterprises distributor info as rich text" do
 
     # -- Purchase email
     complete_purchase_from_checkout_address_page
+    wait_until { ActionMailer::Base.deliveries.length == 1 }
     ActionMailer::Base.deliveries.length.should == 1
     email = ActionMailer::Base.deliveries.last
     email.body.should =~ /Chu ge sai yubi dan bisento tobi ashi yubi ge omote./

spec/features/consumer/checkout_spec.rb

@@ -79,6 +79,42 @@ feature %q{
     page.should have_selector '#delivery-fees span.order-total', :text => '$3.00'
   end
 
+  scenario "changing distributor updates delivery fees" do
+    # Given two distributors and shipping methods
+    d1 = create(:distributor_enterprise)
+    d2 = create(:distributor_enterprise)
+    sm1 = create(:shipping_method)
+    sm1.calculator.set_preference :amount, 1.23; sm1.calculator.save!
+    sm2 = create(:free_shipping_method)
+    sm2.calculator.set_preference :amount, 2.34; sm2.calculator.save!
+
+    # And two products both available from both distributors
+    p1 = create(:product)
+    create(:product_distribution, product: p1, distributor: d1, shipping_method: sm1)
+    create(:product_distribution, product: p1, distributor: d2, shipping_method: sm2)
+    p2 = create(:product)
+    create(:product_distribution, product: p2, distributor: d1, shipping_method: sm1)
+    create(:product_distribution, product: p2, distributor: d2, shipping_method: sm2)
+
+    # When I add the first product to my cart with the first distributor
+    #visit spree.root_path
+    login_to_consumer_section
+    click_link p1.name
+    select d1.name, :from => 'distributor_id'
+    click_button 'Add To Cart'
+
+    # Then I should see shipping costs for the first distributor
+    page.should have_selector 'span.shipping-total', text: '$1.23'
+
+    # When add the second with the second distributor
+    click_link 'Continue shopping'
+    click_link p2.name
+    select d2.name, :from => 'distributor_id'
+    click_button 'Add To Cart'
+
+    # Then I should see shipping costs for the second distributor
+    page.should have_selector 'span.shipping-total', text: '$4.68'
+  end
 
   scenario "buying a product", :js => true do
     login_to_consumer_section
@@ -143,4 +179,5 @@ feature %q{
     # page.should have_content('On Tuesday, 4 PM')
     # page.should have_content('12 Bungee Rd, Carion')
   end
+
 end

spec/models/line_item_spec.rb

@@ -2,17 +2,42 @@ require 'spec_helper'
 
 module Spree
   describe LineItem do
-    it "computes shipping cost for its product" do
-      # Create a shipping method with flat rate of 10
-      shipping_method = create(:shipping_method)
-      shipping_method.calculator.set_preference :amount, 10
+    describe "computing shipping cost for its product" do
+      let(:shipping_method) do
+        sm = create(:shipping_method)
+        sm.calculator.set_preference :amount, 10
+        sm
+      end
+      let(:order) { double(:order, :distributor => nil, :state => 'complete') }
+      let(:line_item) do
+        li = LineItem.new
+        li.stub(:shipping_method).and_return(shipping_method)
+        li.stub(:order).and_return(order)
+        li
+      end
 
-      order = double(:order, :distributor => nil)
+      it "computes shipping cost for its product" do
+        line_item.itemwise_shipping_cost.should == 10
+      end
 
-      subject.stub(:shipping_method).and_return(shipping_method)
-      subject.stub(:order).and_return(order)
+      it "updates shipping method when order has not yet been placed" do
+        %w(cart address delivery resumed).each do |state|
+          order.stub(:state).and_return(state)
+          line_item.should_receive(:set_itemwise_shipping_method)
+          line_item.should_receive(:shipping_method_id_changed?).and_return(true)
+          line_item.should_receive(:save!)
+          line_item.itemwise_shipping_cost
+        end
+      end
 
-      subject.itemwise_shipping_cost.should == 10
+      it "does not update shipping method when order has been placed" do
+        %w(payment confirm complete cancelled returned awaiting_return).each do |state|
+          order.stub(:state).and_return(state)
+          line_item.should_receive(:set_itemwise_shipping_method).never
+          line_item.should_receive(:save!).never
+          line_item.itemwise_shipping_cost
+        end
+      end
     end
   end
 end