Manually reset the order once completed

Spree does not call after_<order.state> methods any more as of
https://github.com/spree/spree/pull/2557, so our #after_complete method
is never triggered and thus the order never reset.

This makes the condition:

```ruby
if current_order.andand.distributor == @order.distributor
```

in app/views/spree/orders/form/_update_buttons.html.haml return false
and as a result the "Back To Cart" button is not shown.

This commit resets the order (emptying the session[:order_id] and
creating a new order, aka. cart) right from the
CheckoutController#update rather than relying on infernal callbacks (of
what the Spree core team itself was unhappy about since long ago
https://github.com/spree/spree/issues/2488). There is the first place
where we know the order has been successfully completed.

app/controllers/checkout_controller.rb

@@ -40,6 +40,8 @@ class CheckoutController < Spree::CheckoutController
         set_default_bill_address
         set_default_ship_address
 
+        reset_order
+
         flash[:success] = t(:order_processed_successfully)
         respond_to do |format|
           format.html do

app/controllers/spree/checkout_controller_decorator.rb

@@ -32,8 +32,4 @@ Spree::CheckoutController.class_eval do
     @order.bill_address ||= preferred_bill_address || last_used_bill_address || Spree::Address.default
     @order.ship_address ||= preferred_ship_address || last_used_ship_address || nil
   end
-
-  def after_complete
-    reset_order
-  end
 end

app/helpers/checkout_helper.rb

@@ -105,17 +105,7 @@ module CheckoutHelper
   end
 
   def reset_order
-    distributor = current_order.distributor
-    token = current_order.token
-
-    session[:order_id] = nil
-    @current_order = nil
-    current_order(true)
-
-    current_order.set_distributor!(distributor)
-    current_order.tokenized_permission.token = token
-    current_order.tokenized_permission.save!
-    session[:access_token] = token
+    ResetOrderService.new(self).call
   end
 
   def payment_method_price(method, order)

app/models/reset_order_service.rb

@@ -0,0 +1,15 @@
+class ResetOrderService < SimpleDelegator
+  def call
+    distributor = current_order.distributor
+    token = current_order.token
+
+    session[:order_id] = nil
+    __getobj__.instance_variable_set(:@current_order, nil)
+    current_order(true)
+
+    current_order.set_distributor!(distributor)
+    current_order.tokenized_permission.token = token
+    current_order.tokenized_permission.save!
+    session[:access_token] = token
+  end
+end

spec/controllers/checkout_controller_spec.rb

@@ -106,6 +106,8 @@ describe CheckoutController do
     end
 
     it "returns order confirmation url on success" do
+      expect(controller).to receive(:reset_order)
+
       order.stub(:update_attributes).and_return true
       order.stub(:state).and_return "complete"
 
@@ -116,6 +118,8 @@ describe CheckoutController do
 
     describe "stale object handling" do
       it "retries when a stale object error is encountered" do
+        expect(controller).to receive(:reset_order)
+
         order.stub(:update_attributes).and_return true
         controller.stub(:state_callback)
 

spec/controllers/spree/checkout_controller_spec.rb

@@ -4,45 +4,40 @@ require 'support/request/authentication_workflow'
 
 
 describe Spree::CheckoutController do
-  include AuthenticationWorkflow
-
   context "After completing an order" do
-    it "should create a new empty order" do
-      controller.current_order(true)
-      controller.send(:after_complete)
-      session[:order_id].should_not be_nil
+    let!(:order) { controller.current_order(true) }
+
+    it "creates a new empty order" do
+      controller.reset_order
+      expect(controller.session[:order_id]).not_to be_nil
     end
 
-    it "should clear the current order cache" do
-      order = controller.current_order(true)
-      controller.send(:after_complete)
-      controller.current_order.should_not == order
+    it "clears the current order cache" do
+      controller.reset_order
+      expect(controller.current_order).not_to eq order
     end
 
-    it "should set the new order's distributor to the same as the old order" do
-      order = controller.current_order(true)
+    it "sets the new order's distributor to the same as the old order" do
       distributor = create(:distributor_enterprise)
       order.set_distributor!(distributor)
 
-      controller.send(:after_complete)
+      controller.reset_order
 
-      controller.current_order.distributor.should == distributor
+      expect(controller.current_order.distributor).to eq distributor
     end
 
-    it "should set the new order's token to the same as the old order, and preserve the access token in the session" do
-      order = controller.current_order(true)
+    it "sets the new order's token to the same as the old order, and preserve the access token in the session" do
+      controller.reset_order
 
-      controller.send(:after_complete)
-
-      controller.current_order.token.should == order.token
-      session[:access_token].should == order.token
+      expect(controller.current_order.token).to eq order.token
+      expect(session[:access_token]).to eq order.token
     end
   end
 
   context "rendering edit from within spree for the current checkout state" do
     let!(:order) { controller.current_order(true) }
     let!(:line_item) { create(:line_item, order: order) }
-    let!(:user) { create_enterprise_user }
+    let!(:user) { create(:user) }
 
     it "redirects to the OFN checkout page" do
       controller.stub(:skip_state_validation?) { true }

spec/features/consumer/shopping/checkout_spec.rb

@@ -245,13 +245,16 @@ feature "As a consumer I want to check out my cart", js: true, retry: 3 do
       describe "purchasing" do
         it "takes us to the order confirmation page when we submit a complete form" do
           toggle_details
+
           within "#details" do
             fill_in "First Name", with: "Will"
             fill_in "Last Name", with: "Marshall"
             fill_in "Email", with: "test@test.com"
             fill_in "Phone", with: "0468363090"
           end
+
           toggle_billing
+
           within "#billing" do
             fill_in "Address", with: "123 Your Face"
             select "Australia", from: "Country"
@@ -259,35 +262,40 @@ feature "As a consumer I want to check out my cart", js: true, retry: 3 do
             fill_in "City", with: "Melbourne"
             fill_in "Postcode", with: "3066"
           end
+
           toggle_shipping
+
           within "#shipping" do
             choose sm2.name
             fill_in 'Any comments or special instructions?', with: "SpEcIaL NoTeS"
           end
+
           toggle_payment
+
           within "#payment" do
             choose pm1.name
           end
 
           expect do
             place_order
-            page.should have_content "Your order has been processed successfully"
+            expect(page).to have_content "Your order has been processed successfully"
           end.to enqueue_job ConfirmOrderJob
 
           # And the order's special instructions should be set
-          o = Spree::Order.complete.first
-          expect(o.special_instructions).to eq "SpEcIaL NoTeS"
+          order = Spree::Order.complete.first
+          expect(order.special_instructions).to eq "SpEcIaL NoTeS"
 
           # And the Spree tax summary should not be displayed
-          page.should_not have_content product.tax_category.name
+          expect(page).not_to have_content product.tax_category.name
 
           # And the total tax for the order, including shipping and fee tax, should be displayed
           # product tax    ($10.00 @ 10% = $0.91)
           # + fee tax      ($ 1.23 @ 10% = $0.11)
           # + shipping tax ($ 4.56 @ 25% = $0.91)
           #                              = $1.93
-          page.should have_content "(includes tax)"
-          page.should have_content with_currency(1.93)
+          expect(page).to have_content '(includes tax)'
+          expect(page).to have_content with_currency(1.93)
+          expect(page).to have_content 'Back To Store'
         end
 
         context "with basic details filled" do