Practice Problems with Worked Answers
On this page 11 headings
1. Which boundary values should be checked for isPrime(num)?
Answer: 0 and 1.
2. For min(x, y), which tests cover both branches?
Answer: (3, 8) returns 3 through the True branch; (9, 4) returns 4 through the False branch.
3. What do {49, 100, 200} establish for num < 50 or num > 150?
Answer: They achieve multiple condition coverage: the first component is True for 49, both are False for 100, and the second is True for 200.
4. What is the difference between a driver and a stub?
Answer: A driver holds the non-local data used by the module under test; a stub is a dummy for a function the module calls. Top down uses stubs; bottom up uses drivers.
5. When does pytest.raises(ValueError) pass?
Answer: It passes when ValueError is raised inside the context.
6. Why does replacing the count with 10 on the second addition fail?
Answer: After two additions of 10, the count should be 20. Replacement leaves 10.
7. What is the Red–Green–Refactor order?
Answer: Write a failing test, implement enough to pass, then refactor while tests pass.
8. Which integration strategy starts with lower-level modules?
Answer: Bottom up integration; drivers supply the non-local data required by the modules.
9. Distinguish smoke, performance and stress testing.
Answer: Smoke testing checks basic functionality before system testing. Performance testing checks non-functional requirements. Stress testing is a type of performance testing beyond design capacity.
10. How is cyclomatic complexity calculated here?
Answer: Number of decision and loop statements + 1 = 3 + 1 = 4; at least four test cases.
11. Why is one passing is_prime(5) test insufficient?
Answer: A function that always returns True would pass. Test non-primes and boundaries too.