def test_time_between_unhappy(calculations):
    start_date = datetime.datetime.now()
    end_date = datetime.datetime.now() - datetime.timedelta(days=5)

    with pytest.raises(ValueError):
        calculations.time_between(start_date, end_date)
def test_time_between_happy(calculations):
    start_date = datetime.datetime.now() - datetime.timedelta(days=5)
    end_date = datetime.datetime.now()

    expected = datetime.timedelta(days=5)
    assert calculations.time_between(start_date, end_date).days == expected.days