'Test preferred variants are applied correctly'

def test_preferred_variants(self):

    update_packages('mpileaks', 'variants', '~debug~opt+shared+static')
    assert_variant_values('mpileaks', debug=False, opt=False, shared=True, static=True)
    update_packages('mpileaks', 'variants', ['+debug', '+opt', '~shared', '-static'])
    assert_variant_values('mpileaks', debug=True, opt=True, shared=False, static=False)
