عرض عملي: تحويل اختبارات منسوخة إلى جدول مُعلْمَر

خطوة بخطوة

1. Show ten near-identical tests for Shop discount and tax rules.
2. Create one @ParameterizedTest with @CsvSource; move the data into rows.
3. Add a readable name template and run; each row reports separately.
4. Add edge rows (zero, maximum discount, rounding).
5. Planned mistake: compare BigDecimal with assertEquals and 100.0 vs 100.00 fails; fix with isEqualByComparingTo.
6. Plant a bug in the calculator and show a row failing.