What is a primary reason for re-running relevant tests after a fix?

• A. To waste time.
• B. To change unrelated aspects.
• C. To ensure no regression.
• D. None.

Answer: (C)

Testing after a fix centers on preventing regressions: you want to confirm that the change actually resolves the issue without introducing new problems in the surrounding code. Re-running relevant tests is regression testing, aimed at ensuring the software’s behavior remains correct in the areas touched by the fix and that existing interfaces still function as expected. This provides confidence before release and helps catch any unintended side effects early. It’s not about wasting time, and it’s not about altering unrelated parts—the goal is to validate stability where the fix was applied.