1. [Ammann and Offutt, “Introduction to Software Testing,” Ch. 8]
Logic Coverage Inactive Clause Coverage CS 4501 / Software Testing
[Ammann and Offutt, “Introduction to Software Testing,” Ch. 8]

2. General Active Clause Coverage (GACC)
Review
p = (a ↔ b)
row a b p pa pb 1 T 2 F 3 4
pa = T
a = T
pa = T
a = F
Can be satisfied by {1,2} x {3,4}
If (1,4) is used, p is always true
If (2,3) is used, p is always false
GACC does not guarantee PC

3. Correlated Active Clause Coverage (CACC)
Review
p = (a ↔ b)
row a b p pa pb 1 T 2 F 3 4
pa = T
a = T
pa = T
a = F
p evaluates to T and F
Only (1,3) and (2,4) satisfy CACC

4. Restricted Active Clause Coverage (RACC)
Review
p = (a ↔ b)
row a b p pa pb 1 T 2 F 3 4
pa = T
a = T
pa = T
a = F
p evaluates to T and F, same minor truth value
Only (1,3) and (2,4) satisfy RACC

5. CACC vs. RACC What is the difference between CACC and RACC?
RACC imposes more constraints on the truth values of minor clauses
RACC requires the the truth values for minor clauses are consistent between the two requirements
In practice?
There are fewer possible truth table row combinations that satisfy RACC
RACC leads to more infeasible test requirements than CACC

6. RACC Leads to Infeasible Requirements
If clauses are independent, there is no problem
If clauses are dependent, some combination of clauses become infeasible
Consider a system with the constraints:
A valve must be open in “operational” mode and closed in all other modes
Mode cannot be in both “operational” and “standby” at the same time
Three clauses:
a = the valve is closed
b = the system mode is operational
c = the system mode is standby
p = valve is closed AND (system is in operational mode OR system is in standby mode)
= a  (b  c)
Constraints: ¬a ↔ b
¬(b  c)

7. CACC and RACC – Infeasible TRs
p = a  (b  c)
Constraints: ¬a ↔ b
¬(b  c)
row a b c p
Constraint violations 1 T
1,2 2 F 3 4 5 6 7 8
CACC can be satisfied by choosing one of the nine pairs
RACC can be satisfied by choosing one of the three pairs
CACC: out of {1,2,3} x {5,6,7}, only (3,6) is feasible
RACC: out of (1,5), (2,6), (3,7), none are feasible

8. Inactive Clause Coverage (ICC)
ACC ensures that “major” clauses do affect the predicates
ICC ensures that “major” clauses do not affect the predicates
Also known as “Reinforced Condition/Decision Coverage” (RCDC)
Inactive Clause Coverage (ICC) : For each p in P and each major clause ci in Cp, choose minor clauses cj, j != i, so that ci does not determine p.
TR has four requirements for each ci:
ci evaluates to true with p true,
ci evaluates to false with p true,
ci evaluates to true with p false,
ci evaluates to false with p false

9. ICC Example p = (¬a  ¬b)  (a  ¬c)  (¬a  c) Major clause: b row apb pc 1 T 2 3 4 5 6 7 8
p = T, pb = F
b = T: rows
b = F: rows
2, 5
4, 7
p = F, pb = F
b = T: rows
b = F: rows 1 3
Do the minor clauses have to have the same values when the major clause is true and false?

10. General Inactive Clause Coverage (GICC)
For each clause ci in predicate p, choose minor clauses such that c does not determine p
ci evaluates to true with p true,
ci evaluates to false with p true,
ci evaluates to true with p false,
ci evaluates to false with p false
Minor clause may differ

11. GICC Example p = (¬a  ¬b)  (a  ¬c)  (¬a  c) Major clause: b row apb pc 1 T 2 3 4 5 6 7 8
p = T, pb = F
b = T: rows
b = F: rows
2, 5
4, 7
Possible tests:
(2,4), (2,7), (5,4), (5,7)
p = F, pb = F
b = T: rows
b = F: rows 1 3
Possible tests:
(1,3)

12. GICC Example (exercise)
p = (¬a  ¬b)  (a  ¬c)  (¬a  c)
Major clause: a
row a b c p pa pb pc 1 T 2 3 4 5 6 7 8
p = T, pa = F
a = T: rows
a = F: rows 4 8
Possible tests:
(4,8)
p = F, pa = F
a = T: rows
a = F: rows -
Possible tests:
No feasible pairs

13. GICC Example (exercise)
p = (¬a  ¬b)  (a  ¬c)  (¬a  c)
Major clause: c
row a b c p pa pb pc 1 T 2 3 4 5 6 7 8
p = T, pc = F
c = T: rows
c = F: rows 7 8
Possible tests:
(7,8)
p = F, pc = F
c = T: rows
c = F: rows -
Possible tests:
No feasible pairs

14. Restricted Inactive Clause Coverage (RICC)
For each clause ci in predicate p, choose minor clauses such that c does not determine p
ci evaluates to true with p true,
ci evaluates to false with p true,
ci evaluates to true with p false,
ci evaluates to false with p false
Minor clause must be the same

15. RICC Example p = (¬a  ¬b)  (a  ¬c)  (¬a  c) Major clause: b
row a b c p pa pb pc 1 T 2 3 4 5 6 7 8
p = T, pb = F
b = T: rows
b = F: rows
2, 5
4, 7
Possible tests:
(2,4), (2,7), (5,4), (5,7)
p = F, pb = F
b = T: rows
b = F: rows 1 3
Possible tests:
(1,3)
Minor clause(s): a, c

16. RICC Example (exercise)
p = (¬a  ¬b)  (a  ¬c)  (¬a  c)
Major clause: a
row a b c p pa pb pc 1 T 2 3 4 5 6 7 8
p = T, pa = F
a = T: rows
a = F: rows 4 8
Possible tests:
(4,8)
p = F, pa = F
a = T: rows
a = F: rows -
Possible tests:
No feasible pairs

17. RICC Example (exercise)
p = (¬a  ¬b)  (a  ¬c)  (¬a  c)
Major clause: c
row a b c p pa pb pc 1 T 2 3 4 5 6 7 8
p = T, pc = F
c = T: rows
c = F: rows 7 8
Possible tests:
(7,8)
p = F, pc = F
c = T: rows
c = F: rows -
Possible tests:
No feasible pairs

18. Logic Coverage Criteria Subsumption
Combinatorial
Clause Coverage
CoC
Restricted Active
RACC
Restricted Inactive
RICC
Correlated Active
CACC
General Inactive
GICC
General Active
GACC CC
Predicate Coverage PC

19. Infeasibility
Subsumption is not always given. Sometimes test requirements cannot be satisfied.
Example:
(a > b  b > c)  (c > a)
(a > b) = true, (b > c) = true, (c > a) true … infeasible
Infeasible test requirements must be recognized and eliminated
Recognizing infeasible test requirements is hard, and in general, undecidable
More complex criteria also produce more infeasible test requirements

20. If RACC test generation fails
Best Effort Strategy
If RACC test generation fails
Combinatorial
Clause Coverage
CoC
Restricted Active
RACC
Restricted Inactive
RICC
Correlated Active
CACC
General Inactive
GICC
General Active
GACC CC
Predicate Coverage PC
Try CACC

21. Summary Predicates are often very simple
In practice, most have only one clause (<= 3 clauses)
With only one clause, PC is enough
With 2 or 3 clauses, CoC is practical
Advantages of ACC and ICC significant for large predicates
CoC is impractical for predicates with many clauses
ICC always guarantees Predicate coverage