Created originally on Bitbucket by timo_jbo (Timo Paulssen)
I adapted two test cases from 3.2/test_math into pypy/module/math.
math.ceil is supposed to return an int, but if a class implements its own ceil, it's allowed to return whatever it likes. OverflowErrors are thrown when passing in inf or -inf and ValueError for NaN. Floor behaves the same way.