Refactor OrderPopulator, add outside level spec

app/models/spree/order_populator_decorator.rb

@@ -1,11 +1,8 @@
 Spree::OrderPopulator.class_eval do
   def populate_with_distribution_validation(from_hash)
-    @distributor = from_hash[:distributor_id].present? ?
-      Enterprise.is_distributor.find(from_hash[:distributor_id]) : nil
-    @order_cycle = from_hash[:order_cycle_id].present? ?
-                     OrderCycle.find(from_hash[:order_cycle_id]) : nil
+    @distributor, @order_cycle = load_distributor_and_order_cycle(from_hash)
 
-    if @distributor && !DistributionChangeValidator.new(@order).can_change_to_distributor?(@distributor)
+    if !distributor_can_supply_products_in_cart(@distributor)
       errors.add(:base, "That distributor can't supply all the products in your cart. Please choose another.")
     end
 
@@ -13,12 +10,7 @@ Spree::OrderPopulator.class_eval do
 
     # Set order distributor and order cycle
     if valid?
-      # Using @order.reload or not performing any reload causes totals fields (ie. item_total)
-      # to be set to zero
-      @order = Spree::Order.find @order.id
-
-      @order.set_distributor! @distributor
-      @order.set_order_cycle! @order_cycle if @order_cycle
+      set_cart_distributor_and_order_cycle @distributor, @order_cycle
     end
 
     valid?
@@ -40,6 +32,31 @@ Spree::OrderPopulator.class_eval do
     end
   end
 
+
+  private
+
+  def load_distributor_and_order_cycle(from_hash)
+    distributor = from_hash[:distributor_id].present? ?
+                    Enterprise.is_distributor.find(from_hash[:distributor_id]) : nil
+    order_cycle = from_hash[:order_cycle_id].present? ?
+                     OrderCycle.find(from_hash[:order_cycle_id]) : nil
+
+    [distributor, order_cycle]
+  end
+
+  def distributor_can_supply_products_in_cart(distributor)
+    !distributor || DistributionChangeValidator.new(@order).can_change_to_distributor?(distributor)
+  end
+
+  def set_cart_distributor_and_order_cycle(distributor, order_cycle)
+    # Using @order.reload or not performing any reload causes totals fields (ie. item_total)
+    # to be set to zero
+    @order = Spree::Order.find @order.id
+
+    @order.set_distributor! distributor
+    @order.set_order_cycle! order_cycle if order_cycle
+  end
+
   def check_distribution_provided_for(variant)
     order_cycle_required = order_cycle_required_for(variant)
     distribution_provided =

spec/models/order_populator_spec.rb

@@ -0,0 +1,77 @@
+require 'spec_helper'
+
+module Spree
+  describe OrderPopulator do
+    let(:order) { double(:order) }
+    let(:currency) { double(:currency) }
+    let(:params) { double(:params) }
+    let(:distributor) { double(:distributor) }
+    let(:order_cycle) { double(:order_cycle) }
+
+    describe "populate" do
+
+      it "checks that distributor can supply all products in the cart" do
+        op = OrderPopulator.new(order, currency)
+
+        op.should_receive(:load_distributor_and_order_cycle).with(params).
+          and_return([distributor, order_cycle])
+        op.should_receive(:distributor_can_supply_products_in_cart).with(distributor).
+          and_return(false)
+        op.should_receive(:populate_without_distribution_validation).never
+        op.should_receive(:set_cart_distributor_and_order_cycle).never
+
+        op.populate(params).should be_false
+        op.errors.to_a.should == ["That distributor can't supply all the products in your cart. Please choose another."]
+      end
+
+      it "doesn't set cart distributor and order cycle if populate fails" do
+        op = OrderPopulator.new(order, currency)
+
+        op.should_receive(:load_distributor_and_order_cycle).with(params).
+          and_return([distributor, order_cycle])
+        op.should_receive(:distributor_can_supply_products_in_cart).with(distributor).
+          and_return(true)
+
+        op.class_eval do
+          def populate_without_distribution_validation(from_hash)
+            errors.add(:base, "Something went wrong.")
+          end
+        end
+
+        op.should_receive(:set_cart_distributor_and_order_cycle).never
+
+        op.populate(params).should be_false
+        op.errors.to_a.should == ["Something went wrong."]
+      end
+
+      it "sets cart distributor and order cycle when populate succeeds" do
+        op = OrderPopulator.new(order, currency)
+
+        op.should_receive(:load_distributor_and_order_cycle).with(params).
+          and_return([distributor, order_cycle])
+        op.should_receive(:distributor_can_supply_products_in_cart).with(distributor).
+          and_return(true)
+        op.should_receive(:populate_without_distribution_validation).with(params)
+        op.should_receive(:set_cart_distributor_and_order_cycle).with(distributor, order_cycle)
+
+        op.populate(params).should be_true        
+      end
+    end
+
+    describe "attempt_cart_add" do
+      it "validates distribution is provided"
+      it "validates variant is available under distributor"
+    end
+
+    describe "validations" do
+      describe "checking distribution is provided for a variant" do
+      end
+
+      describe "checking variant is available under the distributor" do
+      end
+
+      describe "order cycle required for variant" do
+      end
+    end
+  end
+end