1. G&W Chapter 22: Test Cases Software Specification Lecture 29
Prepared by
Stephen M. Thebaut, Ph.D.
University of Florida

2. Part V: Greatly Improving the Odds of Success
Ambiguity Metrics
Technical Reviews
Measuring Satisfaction
Test Cases
Studying Existing Products
Making Agreements
Ending

3. Rationale
Designing black-box test cases jointly with clients early in the requirements process is an extremely effective way to stimulate anticipation of product use (and therefore elicit requirements).
stimulus
response

4. Test Case Forms / Sources
Stimulus-response pairs, as in: “If X happens, the product should do Y.”
Input and output conditions
Causes and Effects
Scenarios / Use-Cases: threads of hypothetical product behavior
Marketing brochures
User manuals

5. Black-Box Coverage Strategies
Equivalence Partitioning: sampling valid and invalid equivalence classes of stimuli (“inputs”).
Boundary Value Analysis: exploring valid and invalid stimuli near constraint boundaries.

6. Black-Box Coverage Strategies (cont’d)
Cause-Effect Analysis: systematic exploration of valid and invalid stimuli combinations.
Intuition and Experience: explore unexpected or unusual product use or environmental scenarios.

7. G&W’s Black-Box Testing Process
Construct test cases by imagining that the product has been built and asking “What if” questions.
Answer the test cases, and discuss with stakeholders to obtain agreement.
Attempting to reach agreement will generally lead to new “What if” questions. Add these to the list, answer them, and repeat the process until the list stabilizes.

8. G&W’s Black-Box Testing Process (cont'd)
Review the list with a team of designers and professional writers to identify over-constrained replies; revise to give the greatest possible design freedom – but no more.
Document the cases so they will become the starting basis for system and acceptance tests.

9. Automatic Test Case Synthesis?
Could test cases (e.g., scenarios – threads of hypothetical product behavior) be generated automatically / semi-automatically during the early stages of RE to stimulate anticipation?

10. Automatic Test Case Synthesis? (cont’d)
One approach: model fragmentary, incomplete (and possibly conflicting) requirements in a rule-base and use a forward-chaining execution engine to generate scenarios of product behavior. (Marcel: Thebaut/ Interrante,1991)

11. G&W Chapter 22: Test Cases Software Specification Lecture 29
Prepared by
Stephen M. Thebaut, Ph.D.
University of Florida