Remove calls to deprecated methods (in both code and specs)

core/app/models/spree/order.rb

@@ -744,8 +744,8 @@ def ship_address_attributes=(attributes)
     # @note This doesn't persist the change bill_address or ship_address
     def assign_default_user_addresses
       if user
-        bill_address = (user.bill_address || user.default_address)
-        ship_address = (user.ship_address || user.default_address)
+        bill_address = user.bill_address
+        ship_address = user.ship_address
         # this is one of 2 places still using User#bill_address
         self.bill_address ||= bill_address if bill_address.try!(:valid?)
         # Skip setting ship address if order doesn't have a delivery checkout step

core/spec/models/spree/concerns/user_address_book_spec.rb

@@ -79,7 +79,6 @@ module Spree
                 user.save_in_address_book(address.attributes, true)
                 expect(user.addresses.count).to eq 3
                 expect(user.ship_address.address1).to eq address.address1
-                expect(user.default_address.address1).to eq address.address1
               end
             end
           end
@@ -243,7 +242,6 @@ module Spree
           it "sets the passed address as default shipping address" do
             subject
             expect(user.ship_address).to eq address
-            expect(user.default_address).to eq address
           end
         end
 
@@ -460,11 +458,6 @@ module Spree
       it "stores the ship_address" do
         expect(subject.ship_address).to eq ship_address
       end
-
-      it "is also available as default_address" do
-        expect(subject.ship_address).to eq ship_address
-        expect(subject.default_address).to eq ship_address
-      end
     end
 
     describe "#ship_address=" do
@@ -565,7 +558,7 @@ module Spree
         allow(Spree::Address).to receive(:immutable_merge).and_return address
       end
 
-      it do
+      it "updates ship_address with its present attributes merged with the passed ones" do
         expect(Spree::Address).to receive(:immutable_merge).with(user.ship_address, attributes)
         expect(user).to receive(:ship_address=).with address
 

core/spec/models/spree/order/checkout_spec.rb

@@ -140,7 +140,7 @@ def assert_state_changed(order, from, to)
             let(:address_kind) { :ship }
             before do
               order.user = FactoryBot.create(:user)
-              order.user.default_address = default_address
+              order.user.ship_address = default_address
               order.next!
               order.reload
             end
@@ -150,7 +150,7 @@ def assert_state_changed(order, from, to)
             let(:address_kind) { :bill }
             before do
               order.user = FactoryBot.create(:user)
-              order.user.default_address = default_address
+              order.user.bill_address = default_address
               order.next!
               order.reload
             end