TGV: theory, principles and algorithms · TGV: theory, principles and algorithms David Reisenberger...

TGV: theory,principles andalgorithms

DavidReisenberger

BasicsTGV overviewIOLTSFormal testpurposes

Principles andalgorithmsSynchronousproductExtractingvisible behaviourTest selectionControllabilityOn-The-Flysynthesis

The Tool

Conclusion

TGV: theory, principles and algorithms

David Reisenberger

May 31, 2012


DavidReisenberger



The Tool

Conclusion

The paper

Claude Jard, Thierry Jeron

Published online 2004, Springer-Verlag


DavidReisenberger



The Tool

Conclusion

TGV

Test generation with verification technology

automatic synthesis of conformance test cases from aformal specification of a (non-deterministic) reactivesystem

”on-the-fly” synthesis


DavidReisenberger



The Tool

Conclusion

Outline

1 BasicsTGV overviewIOLTSFormal test purposes

2 Principles and algorithmsSynchronous productExtracting visible behaviourTest selectionControllabilityOn-The-Fly synthesis

3 The Tool

4 Conclusion


DavidReisenberger



The Tool

Conclusion

Definitions

Test case: testing particular functionality

Test suite: a set of tests

Test: outputs are stimuli for IUT, inputs are observationsof IUT’s outputs

Fail verdict: IUT is rejected

Pass verdict: IUT is accepted

Inconclusive verdict: correct behaviour is observed buttest purpose can’t be reached

Soundness: test cases only reject non-conformant IUT’s

Exhaustiveness: all non-conformant IUT’s are rejected


DavidReisenberger



The Tool

Conclusion

Functional view


DavidReisenberger



The Tool

Conclusion

IOLTS

M = (QM ,AM ,!M , qM0 )AM = AMI [ AMO [ IM

a(i) 2 AM \ IM

⌧(i) 2 IM

Fireable actions: �(q)

Transitions:a�!

Visible behaviour: )Input: ?a

Output: !x

det(M): M without internal actions


DavidReisenberger



The Tool

Conclusion

IOLTS cont.


DavidReisenberger



The Tool

Conclusion

Quiescence

Deadlock: �(q) = ;Output quiescence: �(q) ✓ AMILivelock

deadlock(M) ✓ outputlock(M)quiescent(M) = livelock(M) [ outputlock(M)


DavidReisenberger



The Tool

Conclusion

Suspension automaton �(S)

TP SP


DavidReisenberger



The Tool

Conclusion

det(�(S)) = SVIS


DavidReisenberger



The Tool

Conclusion

Test purpose

TP = (QTP ,ATP ,!TP , qTP0 )AcceptTP : select target behaviour

RefuseTP : cut down specification

Allows e�cient test selection on-the-fly

Smaller than specification but complete (...?)


DavidReisenberger



The Tool

Conclusion

Test purpose cont.

S SP


DavidReisenberger



The Tool

Conclusion

Principles and algorithms


DavidReisenberger



The Tool

Conclusion

Synchronous product

Mark behaviours of S by Accept,Refuse

Accepted behaviour of SP are accepted behaviours of S byTP


DavidReisenberger



The Tool

Conclusion

S ⇥ TP = SP

S TP


DavidReisenberger



The Tool

Conclusion

SPVIS = det(�(SP))

CTG


DavidReisenberger



The Tool

Conclusion

Test selection

Extracting test case by selection of accepted behaviours

ACTGO ✓ AVISIACTGI = A

VISO

L2A: all states that lead to accept

Pass: AcceptVIS

Inconc: direct successors of states in L2A by output inSPVIS

Fail: else

Result: CTG (Complete Test Graph)

TGVLoop, based on Tarjan’s algo (O(n), S(n))


DavidReisenberger



The Tool

Conclusion

Test selection

SPVIS TC


DavidReisenberger



The Tool

Conclusion

Controllability

Extract a controllable subgraph of CTG

Get rid of choices between I/O (pruning)

This can happen during TGVLoop (partially)


DavidReisenberger



The Tool

Conclusion

A test case

CTG


DavidReisenberger



The Tool

Conclusion

On-The-Fly synthesis

perform lazy construction of subgraphs of S , SP , SPVIS

needed functions

initfireablesuccComparison functionFunction to compute membership of Accept/Refuse

goal: reduce size of graphs


DavidReisenberger



The Tool

Conclusion

The Tool

Several software layersCommunicate through APIsEach one is simulation of IOLTS (allows graph traversal)Each level implements one of the algorithmsOutput: test cases in TTCN or graph formats (.aut, .bcg)Can be used to verify manually created test casesSunOS 5, Windows XP, Linux


DavidReisenberger



The Tool

Conclusion

Architecture


DavidReisenberger



The Tool

Conclusion

Timers


DavidReisenberger



The Tool

Conclusion

Conclusion

TGV can synthesize tests from industrial size specs

Drawback: manual creation of test purpose

Still better than manual test case creation

Future: distributed tests, improvements of algorithms

BasicsTGV overviewIOLTSFormal test purposes

Principles and algorithmsSynchronous productExtracting visible behaviourTest selectionControllabilityOn-The-Fly synthesis

The ToolConclusion

TGV: theory, principles and algorithms · TGV: theory, principles and algorithms David Reisenberger...

Documents

Transcript of TGV: theory, principles and algorithms · TGV: theory, principles and algorithms David Reisenberger...