CAST Test Design Techniques 1 — Questions and Answers
Question 1: Which test design technique divides input data into groups where all values in a group are expected to be processed the same way?
- Boundary value analysis
- Equivalence partitioning (Correct answer)
- Decision table testing
- State transition testing
Correct answer: Equivalence partitioning
Equivalence partitioning divides inputs into classes (partitions) where every value in a class is expected to behave identically, reducing the number of test cases needed.
Question 2: When applying boundary value analysis (BVA) to a field that accepts values from 1 to 100, which set of values should be tested?
- 1, 50, 100
- 0, 1, 2, 99, 100, 101 (Correct answer)
- 1, 25, 75, 100
- 0, 50, 101
Correct answer: 0, 1, 2, 99, 100, 101
BVA tests the minimum, minimum+1, maximum-1, maximum, and the values just outside those boundaries (0 and 101), giving 0, 1, 2, 99, 100, 101.
Question 3: A decision table test design technique is MOST useful when:
- Input values form a continuous numeric range
- Multiple conditions combine to produce different actions (Correct answer)
- The system transitions between multiple states
- Test coverage of individual code branches is required
Correct answer: Multiple conditions combine to produce different actions
Decision tables are best suited when the outcome depends on combinations of multiple conditions, systematically capturing all condition/action combinations.
Question 4: In equivalence partitioning, which statement about invalid partitions is CORRECT?
- Only one test case from each invalid partition is needed (Correct answer)
- Invalid partitions should be tested with multiple values
- Invalid partitions need not be tested if valid partitions pass
- Invalid partitions apply only to output values
Correct answer: Only one test case from each invalid partition is needed
Like valid partitions, one representative test case per invalid partition is sufficient because all values within that partition are expected to behave the same way.
Question 5: Which black-box test design technique creates test cases based on cause-effect relationships between inputs and outputs?
- Statement coverage
- Decision table testing (Correct answer)
- Path testing
- Branch coverage
Correct answer: Decision table testing
Decision table testing explicitly models cause-effect relationships by listing conditions (causes) and their corresponding actions (effects) in a tabular format.
Question 6: What is the PRIMARY purpose of pairwise (all-pairs) testing?
- Ensure every statement in the code is executed
- Test all combinations of two input parameters while reducing total test cases (Correct answer)
- Verify state transitions between all system states
- Cover every branch in the control flow graph
Correct answer: Test all combinations of two input parameters while reducing total test cases
Pairwise testing ensures every combination of any two parameters is covered at least once, significantly reducing the number of test cases compared to exhaustive combinatorial testing.
Question 7: Which of the following BEST describes the 'error guessing' test design technique?
- A formal method using mathematical proofs to identify defects
- An experience-based technique where testers use knowledge of typical errors to design tests (Correct answer)
- A structured approach derived from system specifications
- A technique that automates random input generation
Correct answer: An experience-based technique where testers use knowledge of typical errors to design tests
Error guessing relies on the tester's experience and intuition about where defects are likely to occur, targeting historically problematic areas without a formal process.
CAST Test Design Techniques 1
Which test design technique divides input data into groups where all values in a group are expected to be processed the same way?