'Check a betavariate()-like function.'

def _check_betavariate(self, func, ptr):

    r = self._follow_cpython(ptr)
    self._check_dist(func, r.betavariate, [(0.5, 2.5)])
    self.assertRaises(ValueError, func, 0.0, 1.0)
    self.assertRaises(ValueError, func, 1.0, 0.0)
    self.assertRaises(ValueError, func, (-0.5), 1.0)
    self.assertRaises(ValueError, func, 1.0, (-0.5))
