def test_result(i, j, expected):
calc = RpnCalculator()
calc.push(i, j)
v = calc.result()
assert_that(v).is_equal_to(expected)
def test_push_multiple(i, j, k, expected):
calc = RpnCalculator()
calc.push(i, j, k)
v = calc.result()
assert_that(v).is_equal_to(expected)