'Tests westward (negative) magnetic variation.'

def test_west(self):

    (variation, direction) = ('1.34', 'W')
    heading = base.Heading.fromFloats(variationValue=((-1) * float(variation)))
    sentenceData = {'magneticVariation': variation, 'magneticVariationDirection': direction}
    self._fixerTest(sentenceData, {'heading': heading})
