Session 20

1. Session 20 Debriefing HW3 Testing HW3

2. What I looked for in BoundedInteger • Did it compile and run with your tester? • Did it compile with my tester (did it conform to the specs)? • Did you provide all EXPLICIT requirements? • Did you provide all IMPLICIT requirements?

3. What do I mean by implicit requirements?? • Will addition and subtraction handle all int values of input? • “Large” • Negative • Will the code work with non-zero lower bounds?

4. Other things in BoundedInteger • IVS are private • No extra IVs • Reasonable style • Using helper methods? • Constructors? • setValue() uses isLegal() • equals() uses equivalentX() • add() uses increment() or vice versa • Using logic appropriately • Don’t put ifs in methods that return boolean values. • Boolean versus boolean

5. Access methods and the “same” class • Several of you wrote code that said: if (this.getLowerLimit() == other.getLowerLimit() … • But you actually CAN say: if (this.lowerLimit == other.lowerLimit … • Why doesn’t this violate the principle of “private”

6. What I looked for in your tester • Did you name it correctly? • Test both constructors? • Test all fourteen methods? • Did you REALLY test all methods? • Note: How YOU test maybe different from how _I_ would test (whitebox versus blackbox testing).

7. Testing Thoughts • Constructors • Valid bounds, valid start • Valid bounds, invalid start • Valid bounds, no start • Invalid bounds, “valid” start • Invalid bounds, “invalid” start • Invalid bounds, no start • Furthermore, at least ONE attempt to make an instance with negatives involved

8. Testing Thoughts • Mathematical operators • Add/Sub positive number with no roll over. • Add/Sub positive numbers with “just” roll over. • Add/Sub positive numbers with significant roll over. • Add/Sub positive numbers with “double” roll over. • Test some of the above with different lower limits (make sure it isn’t a fluke) • Repeat all of above with negative number inputs.

9. Testing • Accessors (getValue, toString) • PROBABLY only need to test each method once since WHAT they do isn’t state dependent. • Mutator (setValue) • Probably want to fence post (both sides of both limits) • You need to test BOTH pieces of functionality (modification and return value)

10. Testing • Comparison operators (black/white issue again) • Equals (technically eight combinations to test) • Same value, same upper, same lower • Same value, same upper, different lower • Same value, different upper, same lower • Same value, different upper, different lower • Different value, same upper, same lower • Different value, same upper, different lower • Different value, different upper, same lower • Different value, different upper, different lower

11. Testing • Comparison operators (black/white issue again) • Equivalent Value • Technically we only need to look at Same/Diff value • But I actually tested all eight cases from above • Equivalent Limits • Similar here. • isValid • Fenceposting again

12. A “larger” problem that most of you didn’t think about • What happens if either or both bounds are close to the actual bounds of an int??? BoundedInteger bi=new BoundedInteger(0,Integer.MAX_VALUE) bi.add(Integer.MAX_VALUE); bi.add(3);

13. Exam #1 on Wednesday • Based on lectures and readings • Based on CONCEPTS and not code writing • Understand vocabulary • Be able to explain the basic concepts of the course so far