Which statement is true about regression testing in FOSSE?

• A. Regression testing is optional.
• B. It validates only new features.
• C. It tests performance of new modules in isolation.
• D. Regression testing checks that previously working features still work after changes.

Answer: (D)

Regression testing ensures that changes don’t break existing functionality. In FOSSE, updates to a rule, screen, or data interface can ripple through the front-office workflow, so you re-test features that were working before to confirm they still behave correctly. This isn’t optional and isn’t limited to new features; it validates the whole workflow and data integrity to catch unintended side effects. It isn’t about isolated performance testing. For example, after adjusting a pricing rule, you would run end-to-end scenarios from trade entry through settlement to verify all steps still function as before.