Fix failing specs

spec/controllers/split_checkout_controller_spec.rb

@@ -275,7 +275,7 @@ describe SplitCheckoutController, type: :controller do
           context "when adding fails" do
             it "returns 422 and an error message" do
               # Makes adding the voucher fails
-              allow(voucher).to receive(:compute_amount).and_return(0)
+              allow(voucher).to receive(:create_adjustment).and_return(nil)
               allow(Voucher).to receive(:find_by).and_return(voucher)
 
               put :update, params: params

spec/system/consumer/split_checkout_spec.rb

@@ -1115,6 +1115,8 @@ describe "As a consumer, I want to checkout my order" do
         before do
           # Add voucher to the order
           voucher.create_adjustment(voucher.code, order)
+          # Update order so voucher adjustment is properly taken into account
+          order.update_order!
 
           visit checkout_step_path(:summary)
         end