A sample code for https://hychou-svm.medium.com/simplifying-regression-testing-in-python-with-pyartests-decorators-f18b33eacb04

main.py

from artest import autoreg, automock

@autoreg("adder")
def adder(a, b):
    return a + b

# @autoreg("summation")
# def summation(args):
#     # a complex way to implement summation
#     if len(args) == 1:
#         return args[0]
#     s_left = summation(args[:len(args) // 2])
#     s_right = summation(args[len(args) // 2:])
#     s = adder(s_left, s_right)
#     return s
  
@autoreg("summation")
def summation(args):
    s = 0
    for arg in args:
        s = adder(s, arg)
    return s

@autoreg("summation")
def summation(args):
    s = 0
    for arg in args:
        s = adder(s, arg)
    return s

# # Before Modification
# db = [
#     {"date": "2020-01-05", "price": 29},
#     {"date": "2020-01-06", "price": 50},
#     {"date": "2020-01-07", "price": 12},
#     {"date": "2020-01-08", "price": 53},
#     {"date": "2020-01-09", "price": 24},
#     {"date": "2020-01-10", "price": 15},
#     {"date": "2020-01-11", "price": 5},
#     {"date": "2020-01-12", "price": 10},
# ]

# After Modification
db = [
    {"date": "2020-01-05", "price": 129},
    {"date": "2020-01-06", "price": 150},
    {"date": "2020-01-07", "price": 112},
    {"date": "2020-01-08", "price": 153},
    {"date": "2020-01-09", "price": 124},
    {"date": "2020-01-10", "price": 115},
    {"date": "2020-01-11", "price": 105},
    {"date": "2020-01-12", "price": 110},
]

@automock("select_db")
def select_db(start_date, end_date):
    rows = []
    for row in db:
        if start_date <= row["date"] <= end_date:
            rows.append(row)
    return rows

@autoreg("total_costs")
def total_costs(start_date, end_date):
    rows = select_db(start_date, end_date)
    costs = [row["price"] for row in rows]
    return summation(costs)

if __name__ == "__main__":
    print(total_costs("2020-01-06", "2020-01-10"))
    print(total_costs("2020-01-10", "2020-01-12"))
    print(total_costs("2020-01-05", "2020-01-07"))