add unit test to guard againt self-loops that don't exist
add unit test to guard againt self-loops that don't exist

due to drift, control constraints (Uset) and dynamics

necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control