def test_setVariationSign(self):
        """
        Setting the sign of a heading changes the variation sign.
        """
        h = base.Heading.fromFloats(1., variationValue=1.)
        h.setSign(1)
        self.assertEqual(h.variation.inDecimalDegrees, 1.)
        h.setSign(-1)
        self.assertEqual(h.variation.inDecimalDegrees, -1.)

        Setting the sign of a heading changes the variation sign.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/positioning/test/test_base.py