[promo] Ensure that an order has completed successfully in single use promotion test
[promo] Ensure that an order has completed successfully in single use promotion test

Kind of a 'regression test' for this issue brought up by @daddeo2: https://github.com/spree/spree/commit/e9ad6c7a3deb107152a003bbbfc5d80947bb1832#commitcomment-2252676

lzcabrera/spree-1-3-stable,lzcabrera/spree-1-3-stable,lzcabrera/spree-1-3-stable