White-Box Test Design Flashcards
7 cards from real ISTQB practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 White-Box Test Design flashcards as text
Which of the following scenarios would ONLY be detected by condition coverage but NOT by decision coverage alone?
Answer: A fault where one sub-condition in an OR expression is always true, masking a faulty second sub-condition
If one sub-condition in an OR expression is always true, the compound decision always evaluates to true, so decision coverage is satisfied, but the faulty second sub-condition is never exercised as false.
In the context of white-box testing, what is 'code instrumentation'?
Answer: Inserting probes or counters into source code to measure coverage during execution
Code instrumentation inserts measurement probes into the source or bytecode to track which statements, branches, or conditions are executed during test runs.
A program has a cyclomatic complexity of 8. What does this imply about its testability?
Answer: There are at least 8 independent paths requiring at least 8 test cases for basis path coverage
Cyclomatic complexity of 8 means there are 8 linearly independent paths, requiring at least 8 test cases to achieve basis path (path) coverage.
Which white-box technique is MOST appropriate when testing safety-critical avionics software that must comply with DO-178C Level A?
Answer: MC/DC coverage (100%)
DO-178C Level A (most critical) mandates 100% MC/DC coverage because it provides rigorous testing of each condition's independent effect on decisions.
Which statement about 'dead code' is TRUE in the context of white-box testing?
Answer: Dead code can never be executed regardless of the input, and 100% coverage reveals its presence by impossibility
Dead code is unreachable code that no test input can execute; attempting to achieve 100% coverage exposes dead code because its coverage remains at 0% despite all efforts.
A white-box tester uses a control flow graph and identifies 3 independent paths. After executing test cases covering all 3 paths, which statement is MOST accurate?
Answer: All linearly independent execution paths have been exercised at least once
Covering all independent paths means basis path testing is complete, but it does not guarantee absence of defects or coverage of all equivalence classes.
In data flow testing, which anomaly is considered MOST serious from a defect perspective?
Answer: ur anomaly — a variable is used without a prior definition
A ur anomaly (use before definition) is most serious because reading an undefined variable produces unpredictable, potentially dangerous behavior at runtime.