Which type of testing evaluates the stability of critical functionalities?

• A. Sanity testing
• B. Smoke testing
• C. Regression testing
• D. Functional testing

Answer: (B)

Smoke testing is the correct choice because it specifically evaluates whether the critical functionalities of a software build are stable enough for further testing. The purpose of smoke testing is to ensure that the most important functions of the application work as expected before it proceeds to more thorough testing phases. This initial assessment allows testers to quickly identify major issues and decide whether the build is stable enough for more extensive testing activities.

Sanity testing is typically used to verify specific functionalities after changes have been made, ensuring those changes work correctly, but it does not focus broadly on the stability of all critical functionalities. Regression testing checks for defects in existing functionalities after changes to the software, focusing more on ensuring that new code does not break existing features rather than evaluating overall stability of critical functionalities in a newly built application. Functional testing, while it does assess whether the software behaves as expected based on requirements, is more comprehensive and deals with all functionalities, not just critical ones, which smoke testing specifically targets.

Therefore, smoke testing effectively evaluates the stability of critical functionalities before more substantial testing efforts are undertaken.