def test_subtracting_number_from_latest_calculation():
    # ARRANGE #
    calc = Calculator(1)

    # ACT #
    actual = calc.subtract(1)
    expected = 0

    # ASSERT #
    assert actual == expected
def test_subtracting_two_numbers():
    # ARRANGE #
    calc = Calculator()

    # ACT #
    actual = calc.subtract(1, 1)
    expected = 0

    # ASSERT #
    assert actual == expected