'Fails if the _delegate function doesn\'t return a valid function'

def test_nonetype(self):

    xres = IFDRational(72)
    yres = IFDRational(72)
    self.assertIsNotNone(xres._val)
    self.assertIsNotNone(xres.numerator)
    self.assertIsNotNone(xres.denominator)
    self.assertIsNotNone(yres._val)
    self.assertTrue((xres and 1))
    self.assertTrue((xres and yres))
