12014-07-29

JMUSE: Java 프로그램을 위한 돌연변이 기반 오류 추적 시스템

연광흠 , 김문주Software Testing & Verification Group

(SWTV)CS Dept., KAIST

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Motivation: Finding Cause of SW Error is Difficult

• Developers have spent a large amount of time in debugging.• One of the most laborious task of debugging activities is to locate

the cause of failures (i.e., fault), which is called fault localization.

• Research Goal: To develop automated fault location techniques that assist developers effectively locate the cause of program failures (i.e., fault)

Test case #1: assertEquals(3, Example. setMax(3,1))

Test result: pass

Inspectingline by line

public class Example { public int SetMax(int x, int y) {

1: int max ‐= x; // should be ‘max=x;’2: if(max<y){ 3: max = y;4: return max;6: }7: return max;8: } Test result:

fail

== Laborious task

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1: stmt …k: stmt …n: stmt

Key Idea of jMUSE

• Utilize differences between testing result changes of mutating – correct statements– faulty statements

Mutate correct

statement

Mutate faulty statement

...

1: stmt …f: stmt …n: stmt

Test 1Test 2Test 3Test 4Test 5Test 6

: Failed test

: Passed test

What is the mutation?single syntactic code change Ex.: if(a) if(!a) a+b a–b

Test 1Test 2Test 3Test 4Test 5Test 6

Test 1Test 2Test 3Test 4Test 5Test 6

1: stmt …k: stmt …n: stmt

Conjecture 1

Conjecture 2

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jMUSE Overall

Calc. Susp.

Test suite T

Source code of program P

Byte code of Program P

Processing

PITEST

Execution Coverage analysis Mutation

m1

Exec. mn

Stmts. Covered by tests

Test result1

Test resultn

Test result

Exec.

1. Testing the program and analyzing the coverage2. Generating and testing the mutants3. Processing data and calculating suspiciousness using the MUSE metric

Step1

Step2

Step3

Susp.&

Rank

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결과가 좋은 경우

• 41 failing test cases out of 94 test cases (35 array index out of bounds exceptions and 6 null pointer excep-tions)

Faulty statement

• Test cases 를 the golden mutation 에 대해 수행하면 정상적인 프로그램에서 실행했던 것과 같은 test case results 를 얻게 된다 . 따라서 , 모든 failing test cases 가 passing test cases 로 변하기 때문에 높은 suspiciousness 를 얻게 된다 .

jMUSE result: jMUSE generates a golden mutation ‘result[i+namespaces.length]’

The generated mutation 은 the faulty program 이 정상적인 동작을 수행하도록 만든다 .

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결과가 좋지 않은 경우

2014-07-29 5/5

• 2 failing test cases out of 94 test cases (2 assert failed er-rors)

Faulty statement

jMUSE result: jMUSE generates a mutation ‘return null’

• Test cases 를 the generated mutation 에 대해 수행하면 null pointer excep-tion 이 발생하면서 기존 failing test cases 를 포함한 더 많은 test cases 들이 fail하게 된다 .

The generated mutation 은 the faulty program 이 더 많은 error 를 발생하도록 만든다 .

JMUSE: Java 프로그램을 위한 돌연변이 기반 오류 추적시스템