عرض عملي: إعادة هيكلة دالة طويلة مع بقاء الاختبارات خضراء

خطوة بخطوة

1. Run all tests: green.
2. Rename unclear variables with the IDE.
3. Extract Method for the discount block; run tests; commit "Extract calculateDiscount".
4. Planned mistake: also change the rounding "while we are here"; a test turns red. Fix: undo, keep the commit pure, and do the change later in a separate commit.
5. Replace double money with the Money record where tests allow.
6. Show the final method: short, readable, tests green.

اختبر فهمك