Testing, Debugging & Code Optimization Flashcards

Which testing approach tests the internal logic and structure of the code rather than just its external behavior?

Answer: White-box testing

White-box testing examines the internal code structure, branches, and paths, unlike black-box testing which only evaluates inputs and outputs.

What is a 'breakpoint' in the context of debugging?

Answer: A marker that pauses execution so the developer can inspect state

A breakpoint is a deliberate stopping point set by the developer in a debugger to pause program execution and examine variables and flow.

Which metric measures the percentage of source code lines executed during testing?

Answer: Code coverage

Code coverage (specifically line coverage) reports what percentage of code lines were executed by the test suite.

What is the purpose of a stub in unit testing?

Answer: To replace a real dependency with a minimal controlled implementation

A stub replaces a real dependency (like a database or API) with a simple controlled version so the unit under test can run in isolation.

Which optimization technique moves a loop-invariant computation outside of the loop?

Answer: Loop hoisting (code motion)

Loop hoisting (also called loop-invariant code motion) moves calculations whose result does not change across iterations outside the loop to avoid redundant work.

What does 'regression testing' primarily verify?

Answer: Previously working functionality has not been broken by recent changes

Regression testing re-runs existing tests after code changes to confirm that previously working behavior has not been inadvertently broken.

In big-O notation, which complexity grows most slowly as input size increases?

Answer: O(log n)

O(log n) grows much more slowly than linear O(n) time, making logarithmic algorithms highly efficient for large inputs.