ISTQB White-Box Test Design 5

Question 1

Which of the following is NOT a white-box (structural) testing technique?

Accepted Answer

Equivalence partitioning

Answer

Equivalence partitioning is a black-box technique based on input domain analysis, not on code structure examination.

Question 2

A software component has the Boolean expression `if (x > 0 && y != 0)`. To achieve MC/DC, which set of test cases is SUFFICIENT?

Accepted Answer

TC1: x=1,y=1 (T,T); TC2: x=-1,y=1 (F,T); TC3: x=1,y=0 (T,F)

Answer

MC/DC requires each condition to independently affect the outcome: TC1 shows T,T→T; TC2 changes only x to show F,T→F; TC3 changes only y to show T,F→F — three test cases suffice.

Question 3

When a white-box tester calculates cyclomatic complexity using the formula V(G) = P + 1, what does 'P' represent?

Accepted Answer

The number of predicate (decision) nodes in the control flow graph

Answer

In the formula V(G) = P + 1, P is the number of predicate (binary decision) nodes in the control flow graph.

Question 4

Which coverage criterion is MOST effective at detecting faults caused by incorrect variable initialization before first use?

Accepted Answer

Data flow coverage (all-defs)

Answer

Data flow coverage specifically tracks definition-use pairs and can identify ur anomalies where variables are used before a valid definition, directly targeting initialization faults.

Question 5

A tester achieves 100% branch coverage on a function. Which of the following statements is TRUE?

Accepted Answer

100% statement coverage is also achieved

Answer

Branch coverage subsumes statement coverage — if every branch (true and false outcome of every decision) is exercised, every reachable statement must have been executed.

ISTQB - International Software Testing Qualifications Board Practice Test

ISTQB - International Software Testing Qualifications Board Practice Test

ISTQB White-Box Test Design 5