Consider awaiting_return, returned in balance

These states are reached when the order is complete and shipped. An
admin can create a new return authorization, which will set the order in
`awaiting_return` state. It's only after, when we call
`return_authorization#receive` that the return authorization moves to
`received` state and the order to `returned`.

You can do so from the UI by editing the return authorization and
clicking on Receive. However, we didn't find any order in such state in
UK, FR and AU. The UX is quite obfuscated. That must be why no users
clicked on it.

The `returned` state cannot count for the balance as is, since some of
the products are returned to the shop. That's enough for now.

app/services/customers_with_balance.rb

@@ -22,7 +22,7 @@ class CustomersWithBalance
   def outstanding_balance
     <<-SQL.strip_heredoc
        SUM(
-         CASE WHEN state = 'canceled' THEN payment_total
+         CASE WHEN state IN #{non_fulfilled_states_group.to_sql} THEN payment_total
               WHEN state IS NOT NULL THEN payment_total - total
          ELSE 0 END
        ) AS balance_value
@@ -43,8 +43,19 @@ class CustomersWithBalance
     Arel::Nodes::NotIn.new(Spree::Order.arel_table[:state], states_group)
   end
 
+  def non_fulfilled_states_group
+    states_group = non_fulfilled_states.map { |state| Arel::Nodes.build_quoted(state) }
+    Arel::Nodes::Grouping.new(states_group)
+  end
+
   # All the states an order can be in before completing the checkout
   def prior_to_completion_states
     %w(cart address delivery payment)
   end
+
+  # All the states of a complete order but that shouldn't count towards the balance. Those that the
+  # customer won't enjoy.
+  def non_fulfilled_states
+    %w(canceled returned)
+  end
 end

spec/services/customers_with_balance_spec.rb

@@ -142,6 +142,39 @@ describe CustomersWithBalance do
       end
     end
 
+    context 'when an order is awaiting_return' do
+      let(:payment_total) { order_total }
+
+      before do
+        order = create(:order, customer: customer, total: order_total, payment_total: 0)
+        order.update_attribute(:state, 'checkout')
+        order = create(:order, customer: customer, total: order_total, payment_total: payment_total)
+        order.update_attribute(:state, 'awaiting_return')
+      end
+
+      it 'returns the customer balance' do
+        customer = customers_with_balance.query.first
+        expect(customer.balance_value).to eq(payment_total - total)
+      end
+    end
+
+    context 'when an order is returned' do
+      let(:payment_total) { order_total }
+      let(:non_returned_orders_total) { order_total }
+
+      before do
+        order = create(:order, customer: customer, total: order_total, payment_total: 0)
+        order.update_attribute(:state, 'checkout')
+        order = create(:order, customer: customer, total: order_total, payment_total: payment_total)
+        order.update_attribute(:state, 'returned')
+      end
+
+      it 'returns the customer balance' do
+        customer = customers_with_balance.query.first
+        expect(customer.balance_value).to eq(payment_total - non_returned_orders_total)
+      end
+    end
+
     context 'when there are no orders' do
       it 'returns the customer balance' do
         customer = customers_with_balance.query.first