fails:Integer#upto [stop] when self and stop are Fixnums when no block is given returned Enumerator size raises an ArgumentError for non-numeric endpoints
fails:Integer#upto [stop] when self and stop are Fixnums when no block is given returned Enumerator size returns stop - self + 1
fails:Integer#upto [stop] when self and stop are Fixnums when no block is given returned Enumerator size returns 0 when stop < self
