Add spec for user default address setter

spec/services/user_default_address_setter_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe UserDefaultAddressSetter do
+  let(:customer_address) { create(:address, address1: "customer road") }
+  let(:order_address) { create(:address, address1: "order road") }
+  let(:customer) do
+    create(:customer, bill_address: customer_address, ship_address: customer_address)
+  end
+  let(:order) do
+    create(:order, customer: customer, bill_address: order_address, ship_address: order_address)
+  end
+  let(:user) { create(:user) }
+
+  let(:setter) { UserDefaultAddressSetter.new(order, user) }
+
+  describe '#set_default_bill_address' do
+    it "sets the user and customer bill address to the order bill address" do
+      setter.set_default_bill_address
+
+      expect(user.bill_address).to eq order.bill_address
+      expect(order.customer.bill_address).to eq order.bill_address
+    end
+  end
+
+  describe '#set_default_ship_address' do
+    it "sets the user and customer ship address to the order ship address" do
+      setter.set_default_ship_address
+
+      expect(user.ship_address).to eq order.ship_address
+      expect(order.customer.ship_address).to eq order.ship_address
+    end
+  end
+end