Test Case Design Techniques Questions and Answers

Answer: D

The structure not among the loop classes is the Structured loop.

Loop testing, a white-box technique described by Beizer and in Pressman, considers four classes of loops: simple loops, nested loops, concatenated loops and unstructured loops. Each has its own test strategy; for simple loops, for example, the tests skip the loop, pass through once, twice, m times, and n - 1, n and n + 1 times.

The fourth class is the unstructured loop, which should be redesigned to use structured programming constructs. 'Structured loop' is not one of the classes.

Answer: C

The cyclomatic complexity is 4.

For a flow graph with E edges and N nodes (the paper's 'modes'), McCabe's measure is

\[ \begin{aligned} V(G) &= E - N + 2 \\ &= 5 - 3 + 2 = 4 \end{aligned} \]

-2 is what you get by computing N - E, 2 omits the edges and nodes difference, and 8 adds E and N.

Answer: A

Basis path testing is a whitebox testing technique.

Basis path testing (printed 'Basic path'), proposed by Tom McCabe, draws the control flow graph of the code, computes its cyclomatic complexity, and derives a set of independent paths that tests must execute so that every statement and branch is exercised at least once.

Because it is designed from the internal structure of the code, it is white-box testing. Black-box techniques, such as equivalence partitioning and boundary value analysis, use only the specification, so the other options are wrong.

Answer: C

An independent path introduces (i) or (ii) or both.

In basis path testing, an independent path is any path through the program that introduces at least one new set of processing statements or a new condition. On the flow graph, it must traverse at least one edge not traversed by the paths already defined.

So a path qualifies if it brings in new conditions, new processing statements, or both. Restricting it to conditions alone or to statements alone is too narrow, and 'neither' would make every path count as independent.

Answer: D

The dead or unreachable code is on lines 4, 6, 7, 10.

• Line 4: b is set to 25 but never used before the function returns, so it is a dead variable.
• Lines 6-7: a is 24 and never changes, so the condition a != 24 is always false and the printf can never execute.
• Line 10: it comes after the return on line 9, so it is unreachable.

Line 8 is live: it computes \(c = 24 \lt\lt 2 = 96\), which line 9 returns. So option C, which includes line 8, is wrong, and A and B each leave out a line that is dead.