Normalize symmetries

동일한 문제를 서로 다른 방식으로 풀고 있는 코드가 있다면 동일한 방식으로 변환하기. 켄트 벡이 제안하는 타이딩 중 하나.

The same problem may be solved differently at different times or by different people. That’s okay, but it makes for difficult reading. As a reader, you’d like consistency. If you see a pattern, you can confidently jump to the conclusion that you know what’s going on. … Convert one of the variants into that way. Tidy one form of unnecessary variation at a time.

Test-driven development: by example에서 말하는 차이를 제거하기와 유사하다.