Software Testing Case Studies & Practical Application 2

Question 1

A team discovers that 80% of defects are concentrated in 20% of the modules during a release cycle. Which testing principle does this illustrate?

Accepted Answer

Defect clustering

Answer

Defect clustering states that defects tend to concentrate in a small number of modules, so testing effort should focus on those high-risk areas.

Question 2

An e-commerce site's checkout process fails only when users apply a discount code AND pay with a gift card simultaneously. What type of testing would have best caught this defect?

Accepted Answer

Pairwise (combinatorial) testing

Answer

Pairwise testing systematically covers combinations of inputs, making it well-suited to catch defects that only appear when specific feature pairs interact.

Question 3

A QA engineer runs the same regression suite every sprint for six months and defect detection drops to near zero, yet production incidents continue. This is most likely caused by:

Accepted Answer

The pesticide paradox

Answer

The pesticide paradox describes how repeatedly running the same tests causes them to stop finding new defects, requiring tests to be regularly reviewed and updated.

Question 4

During UAT, business users reject a feature that passed all functional tests. The most likely root cause is:

Accepted Answer

Requirements were not validated with stakeholders early enough

Answer

UAT failures after passing functional tests typically indicate a gap between documented requirements and actual stakeholder expectations, caused by insufficient upfront validation.

Question 5

A banking app passes all security tests in a staging environment but is breached in production. Which factor is the most plausible cause?

Accepted Answer

Staging environment had different network configurations and security controls than production

Answer

Environment discrepancies between staging and production—such as firewall rules, TLS settings, or service configurations—are a common root cause of defects that only appear in production.

Software Testing Practice Test

Software Testing Practice Test

Software Testing Case Studies & Practical Application 2