'Setting the sign of a heading to values that aren\'t C{-1} or C{1}
raises C{ValueError} and does not affect the heading.'

def test_setBadVariationSign(self):

    h = base.Heading.fromFloats(1.0, variationValue=1.0)
    self.assertRaises(ValueError, h.setSign, (-50))
    self.assertEqual(h.variation.inDecimalDegrees, 1.0)
    self.assertRaises(ValueError, h.setSign, 0)
    self.assertEqual(h.variation.inDecimalDegrees, 1.0)
    self.assertRaises(ValueError, h.setSign, 50)
    self.assertEqual(h.variation.inDecimalDegrees, 1.0)
