Wodel: A Domain-SpecificLanguage for Model Mutation

Universidad Autónoma de Madrid (Spain)

P. Gómez-Abajo , E. Guerra, J. de Lara{Pablo.GomezA, Esther.Guerra, Juan.deLara}@uam.es

http://www.miso.es

modelling & software engineeringresearch group

SAC’2016, Pisa (Italy)

• A model mutation is a variation of a seed model by the application of

one or more mutation operators.

• Model mutation has many applications:

• Model transformation testing.

• Model-based software testing.

• Software product lines testing.

• Automated generation of exercises.

• Evolutionary algorithms.

• …

2

0

101

0

110

1

010

Seed model

Mutant models

Wodel

Seed model

...

if (a == true) then

...

...

if (a != true) then

...

Mutant model

What is a Model Mutation?

Motivation• Existing frameworks for model mutation:

• are specific for a language (e.g., logic formula).

• or specific for a domain (e.g., testing).

• mutation operators are manually encoded.

• We propose the DSL Wodel for model mutation:

• high-level mutation primitives.

• independence from target language and domain.

• compiled into Java code.

• extensible through post-processors.

3

4

seedmodels

Meta-Model«conforms»

WODELprogram

domain-specificartefacts/

applications

1

2

WODEL

enginemodel

mutants

Post-

processing

4

«conforms»

3

Overview

Wodel: example5

Automaton

name: String

StateTransition

*

name: StringisInitial: booleanisFinal: boolean

src

tar symbol0..1

states* * transitions

inv1: self.states->one(s | s.isInitial)

inv2: self.states->exists(s | s.isFinal)

inv3: self.alphabet->forAll (a1, a2 |

a1.symbol = a2.symbol

implies a1 = a2)

alphabet

Symbol

symbol: String

generate 3 mutants in "out/" from "evenBinary.fa"

metamodel "http://fa.com"

with commands {

s0 = modify one State where {isFinal = true} with {reverse(isFinal)}

s1 = create State with {isFinal = true}

t0 = create Transition with {src = s0, tar = s1, symbol = one Symbol}

}

Wodel: mutation operators6

// object/ref creation

create State

create reference tar in

one Transition

// objet/ref modification

modify one State

with {isFinal = true}

modify source src from

one Transition

modify target tar from

one Transition

// object/ref deletion

remove one State

remove reference tar in

one Transition

// composite mutation

[

s0 = create State

modify s0 with {name = 's0'}

]

Mutation

min: int=1

max: int=1

CreateObject

ObjectEmitter EClass

type

0..1

name: String[0..1]

ObjectSelection

Strategy

container 0..1

EReference

0..1refType

AttributeSet EAttribute

attributes

*

Attribute

Init

Attribute

Swap

{ordered}

Attribute

Copy

object 0..1

Modify

Information

object0..1

attributes*attributes *

Attribute

Type

value

Composite

Mutation

*

ModifySource

Reference

…

ObjectSelection

Strategy

sourc

e

newSource

EReference

refType 0..1

7

Screenshot of the Wodel IDE

seed

models

DSL

meta-

model

postProc

WODEL

engineeditor (Xtext)

code gen (Xtend)

Java codemodel

mutants

code completion, validator

WODEL

program

«conforms»

check

generate, compile, execute

Architecture of the environmentTool support

8

1....

2.// create transition

3.EClass transitionClass = (EClass)epackage.getEClassifier("Transition");

4.EObject transition = EcoreUtil.create(transitionClass);

5.

6.// search object automaton in model

7.EObject automaton = null;

8.for (TreeIterator<EObject> it = seed.getAllContents(); it.hasNext();) {

9. automaton = it.next();

10. if (automaton.eClass().getName().equals("Automaton")) {

11. // add transition to automaton

12. EStructuralFeature feature = 13. automaton.eClass().getEStructuralFeature("transitions");

14. ((List<EObject>)automaton.eGet(feature)).add(transition);

15. // set random state as source of the transition

16. feature = automaton.eClass().getEStructuralFeature("states");

17. List<EObject> states = (List<EObject>)automaton.eGet(feature);

18. EObject randomState = states.get(rand.nextInt(states.size()));

19. feature = transitionClass.getEStructuralFeature("src");

20. transition.eSet(feature, randomState);

21....

Java code generationcreate Transition with {symbol = one Symbol}

Wodel-Edu: Model Mutationfor the Generation of Exercises

9

postProc

WODEL

engine

WODEL-

EDUDSL eduTest

DSL

modelDraw

mutants

model

rendering

descriptioncode gen

learning

environment

exercises

description

Architecture of the Wodel-Edu plug-in Generated application

• Wodel is a DSL for model mutation:• high-level mutation primitives.

• domain-independent.

• support for composite mutations.

• non-repeated mutants, conformance checking.

• compiled into Java.

• extensible for different applications.

• Wodel-Edu: automated generation of exercises

via model mutation

10

Conclusions

• Extend Wodel with new mutation primitives and a

rule policy language

• Develop new plugins for Wodel (e.g., for model-

based testing, evolutionary computation…)

• Extend Wodel-Edu to support the generation of

more complex learning environments

11

Future Work

12

You can get the source code of this project on

GitHub:

http://gomezabajo.github.io/Wodel/

Short video demo:

https://youtu.be/GBfXH0Rf-fI

Thank you!!

Pablo.GomezA@uam.es