ISTQB Black-Box Test Design 3 — Questions and Answers
Question 1: A tester applies cause-effect graphing to a module and then derives test cases from it. What intermediate artifact is typically produced?
- A state transition table
- A decision table (Correct answer)
- An equivalence class list
- A boundary value matrix
Correct answer: A decision table
Cause-effect graphing converts the logic of causes and effects into a decision table, from which test cases are derived.
Question 2: Which coverage criterion ensures that every valid and invalid equivalence class is exercised at least once?
- Statement coverage
- Branch coverage
- Equivalence partition coverage (Correct answer)
- Decision coverage
Correct answer: Equivalence partition coverage
Equivalence partition coverage requires at least one test for each identified valid and invalid partition.
Question 3: A shopping cart applies a 10% discount when the order total is between $50 and $99, and a 20% discount for $100 or more. Using EP, how many valid partitions exist for the discount logic?
- 1
- 2
- 3 (Correct answer)
- 4
Correct answer: 3
Three valid partitions exist: below $50 (no discount), $50–$99 (10%), and $100+ (20%).
Question 4: In state transition testing, which coverage level requires that every valid transition be exercised at least once?
- 0-switch coverage (Correct answer)
- 1-switch coverage
- 2-switch coverage
- All-paths coverage
Correct answer: 0-switch coverage
0-switch (transition) coverage requires executing every individual valid state transition at least once.
Question 5: A form field accepts months of the year as integers. Which value would be in an INVALID equivalence class?
- 1
- 6
- 12
- 13 (Correct answer)
Correct answer: 13
Valid months are 1–12; the value 13 falls outside this range and belongs to an invalid equivalence class.
Question 6: Which black-box technique is BEST suited for testing complex business rules involving multiple conditions and their combinations?
- Boundary value analysis
- State transition testing
- Decision table testing (Correct answer)
- Use case testing
Correct answer: Decision table testing
Decision table testing systematically covers all combinations of conditions and their resulting actions, ideal for complex business logic.
Question 7: A pairwise (all-pairs) testing tool is used to reduce test cases for a feature with 5 parameters. What is the primary goal of this approach?
- Ensure all boundary values are tested
- Cover every combination of any two parameter values (Correct answer)
- Verify all valid state transitions
- Test all possible input combinations
Correct answer: Cover every combination of any two parameter values
Pairwise testing ensures every pair of parameter values is covered at least once, significantly reducing the total number of test cases.
ISTQB Black-Box Test Design 3
A tester applies cause-effect graphing to a module and then derives test cases from it.
What intermediate artifact is typically produced?