'Check the behavior of the || operator with 0'

def test_parallel_resistors_with_zero(self):

    self.assertTrue(numpy.isnan(calc.evaluator({}, {}, '0||1')))
    self.assertTrue(numpy.isnan(calc.evaluator({}, {}, '0.0||1')))
    self.assertTrue(numpy.isnan(calc.evaluator({'x': 0.0}, {}, 'x||1')))
