6. Common Words / Вирішуємо задачі на Python CheckIO Українською

# -------------      tasks/common_words.py   ---------------

def checkio(first, second):
    first = set(first.split(","))
    second = set(second.split(","))

    res = first.intersection(second)
    return ",".join(sorted(res))

# -----------           tests/test_common_words.py    -----------------

import pytest
from tasks.common_words import checkio


@pytest.mark.parametrize(["item1", "item2", "res"], [
    ["hello,world", "hello,earth", "hello"],
    ["hello,world,hello", "hello,earth,hello", "hello"],
    ["one,two,three", "four,five,six", ""],
    ["one,two,three", "four,five,one,two,six,three", "one,three,two"],
])
def test_common_words(item1, item2, res):
    assert checkio(item1, item2) == res