1. Delta-Oriented Testing for Finite State Machines
Mahsa Varshosaz, Harsh Beohar
Centre for Research on Embedded Systems (CERES)
Halmstad University
AVOCS 2014

2. Testing a family of software
Motivation
Testing a family of software

3. Motivation (cont)

4. Outline
Model Based Testing
W-Method
Delta-oriented W-Method

5. Model Based Testing … LTS FSM System Model Test Case Generation
Implementation
Test Execution

6. Finite State Machine Inputs I={a,b} Outputs O={0,1} s0 s1 s2 b/0 b/0

7. Model Assumptions Fully specified ∀i∈I Deterministic Minimal ≢ s s s

8. W-Method Basis: FSM test models
Goal: Establish conformance between specification and implementation

9. Transition Cover Set (P)
Goal: Checking existence of output faults
P={ƹ ,a,b,a,aa,aaa,aab} s0 s2 s1
b/0
b/1
a/1
a/0 s0 b a s0 s1 a b s0 s2 b a s0 s2

10. Characterizing Set (W)
Goal: Checking existence of transfer faults
W={a,b} s0 s2 s1
b/0
b/1
a/1
a/0
Input /state s0 s1 s2 a 1 b

11. Test Cases The set of test cases to be executed R.P.W
R : the reset sequence

12. Outline
Model Based Testing
W-Method
Delta-oriented W-Method

13. Delta-Oriented ModelingPi
Deltai … …
Core
Model
Deltan
Delta1 P1 Pn

14. Delta Oriented Testing…
Core Model
(M)
∆(M)1
∆(M)i
∆(M)n …
Generating Test Cases
Generating DeltaTest Cases
Mi’
Executing Test

15. FSM Delta ∆(M)=(S∆,I∆,O∆, μ∆ ,λ∆ ) S ∆ non-empty set of states
I ∆ , O ∆ set of inputs and outputs
μ ∆ : (S ⋃ S ∆) x I ∆ ⟶ (S ⋃ S ∆)
λ ∆ : (S ⋃ S ∆) x I ∆ ⟶ O ∆ ⋃ τ

16. FSM Delta (Example) s0 s3 t3 s1 s2 t1 t2 a,b/0 a/1 a,b/1 c/1 b/0 c/0
a,c/0
b,c/1
a/0
b/0
b,c/1
b/0

17. Delta Application Apply(M, ∆(M))= (s0, S’, I’, O’, μ’, λ’)
S’= S ⋃ S∆ I’=I∆ O’=O∆
μ∆ (s, a) if (s, a) ∈ Dom(μ∆ )
μ’(s, a) = μ (s, a) if a ∈ I ∧ (s, a) ∉Dom(μ∆ )
s otherwise
λ∆(s, a) if (s, a) ∈ Dom(λ∆)
λ’(s, a) = λ (s, a) if a ∈ I ∧ (s, a) ∉Dom(λ∆ )
τ otherwise

18. Delta Application (Example)
a,b/0
a/1 s0
a,b/1
b/1 s3
c/1 t3
b/0
c/0
c/1
c/0
a/1
a,b/1 s1 s2 t1 t2
a,c/0
b,c/1
a/0
b/0
b,c/1
b/0

19. Test Criteria Two criteria for solutions
Correctness
Efficiency
Considering an SPL with n products
∆(M)i
Core Model
(M)
M’i

20. Correctness

21. Efficiency

22. Work in Progress Developing algorithms for computing:
Characterizing set
Transition cover set
Extending the delta definition
Implementing the delta oriented method

23. Thank you