ISTQB White-Box Test Design 3

Question 1

A control flow graph has 12 edges, 10 nodes, and 1 connected component. What is its cyclomatic complexity?

Accepted Answer

4

Answer

Cyclomatic complexity V(G) = E - N + 2P = 12 - 10 + 2(1) = 4, indicating 4 independent paths.

Question 2

Which of the following BEST describes 'basis path testing'?

Accepted Answer

Testing a set of linearly independent paths derived from the control flow graph

Answer

Basis path testing derives a set of linearly independent paths from the control flow graph, where the count equals the cyclomatic complexity.

Question 3

In white-box testing, what does a 'du-path' represent in data flow analysis?

Accepted Answer

A path from where a variable is defined to where it is used

Answer

A du-path (definition-use path) traces the execution path from where a variable is defined (assigned) to where it is subsequently used.

Question 4

A condition `(A || B) && C` is evaluated. How many test cases are required to achieve full condition coverage (each atomic condition true and false at least once)?

Accepted Answer

3

Answer

Full condition coverage requires each atomic condition (A, B, C) to take both true and false values, which can be achieved with 3 carefully chosen test cases (though 4 is safer in practice, the minimum is 3).

Question 5

What is the PRIMARY weakness of achieving only 100% decision coverage without achieving 100% condition coverage?

Accepted Answer

Individual conditions within a compound predicate may never be evaluated as false

Answer

Decision coverage only requires each branch outcome (true/false) to be executed once, but individual sub-conditions within a compound predicate may never independently evaluate to false.

ISTQB - International Software Testing Qualifications Board Practice Test

ISTQB - International Software Testing Qualifications Board Practice Test

ISTQB White-Box Test Design 3