ソースコード、テストコード、テストデータを分離

hoge.py

# -*-coding: utf-8 -*-


def add(x, y):
    return x + y

hoge_testdata.csv

hoge_testdata.json

[
    {"expected": 2, "x": 1, "y": 1},
    {"expected": 3, "x": 2, "y": 1},
    {"expected": 4, "x": 4, "y": 0}
]

test_hoge.py

# -*-coding: utf-8 -*-

import unittest
import csv
from hoge import add


def get_testdata(filename):
    if filename is  None:
        raise IOError("filename cannot empty.")
    rows = []
    with open(filename, mode='r') as f:
        reader = csv.reader(f)
        next(reader) # skip header coloumns
        rows = [row for row in reader]
    return rows


def get_testdata_from_json(filename):
    if filename is  None:
        raise IOError("filename cannot empty.")
    data = []
    with open(filename, mode='r') as f:
        data = json.load(f)
    return data


class TestHoge(unittest.TestCase):

    def test_add(self):
        test_data = get_testdata("hoge_testdata.csv")
        for data in test_data:
            result = add(int(data[1]), int(data[2]))
            self.assertEqual(int(data[0]), result)

    #jsonのが直感的でいいね！
    def test_add_from_json(self):
        test_data = get_testdata_from_json("hoge_testdata.json")
        for data in test_data:
            result = add(data['x'], data['y'])
            self.assertEqual(data['expected'], result)


if __name__ == "__main__":
    unittest.main()