YES
LCTRS
  Theories
    Core, Ints
  Sorts
    Unit
  Signature
    sum: Int -> Int
    test: Int -> Unit
  Rules
    test(!x) -> test(!y) [and(>(!x, 0), !x = +(!y, 1))]
    sum(!x) -> +(!x, sum(-(!x, 1))) [<(0, !x)]
    sum(0) -> 0
    sum(!x) -> 0 [<(!x, 0)]
RPO with precedence:
  {and = test sum > < 1 0 - +}

Elapsed Time:  34.86 ms