文献翻译彭言海.docx
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文献翻译彭言海.docx
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文献翻译彭言海
毕业设计(论文)
文献翻译
学院名称:
计算机科学与技术学院
班级:
本09软件02班
学号:
20094350244
学生姓名:
朱诗鑫
2013年03月11日
SOFTWARETESTING
Abstract-SoftwareTestingisanempiricalinvestigationconductedtoprovidestakeholderswithinformationaboutthequalityoftheproductorserviceundertest,withrespecttothecontextinwhichitisintendedtooperate.Thisincludes,butisnotlimitedto,theprocessofexecutingaprogramorapplicationwiththeintentoffindingsoftwarebugs.
Testingcannevercompletelyestablishthecorrectnessofcomputersoftware.Instead,itfurnishesacriticismorcomparisonthatcomparesthestateandbehavioroftheproductagainstoracles—principlesormechanismsbywhichsomeonemightrecognizeaproblem.Theseoraclesmayinclude(butarenotlimitedto)specifications,comparableproducts,pastversionsofthesameproduct,inferencesaboutintendedorexpectedpurpose,userorcustomerexpectations,relevantstandards,applicablelaws,orothercriteria.
Overitsexistence,computersoftwarehascontinuedtogrowincomplexityandsize.Everysoftwareproducthasatargetaudience.Forexample,theaudienceforvideogamesoftwareiscompletelydifferentfrombankingsoftware.Therefore,whenanorganizationdevelopsorotherwiseinvestsinasoftwareproduct,itpresumablymustassesswhetherthesoftwareproductwillbeacceptabletoitsendusers,itstargetaudience,itspurchasers,andotherstakeholders.Softwaretestingistheprocessofattemptingtomakethisassessment.AstudyconductedbyNISTin2002reportsthatsoftwarebugscosttheU.S.economy$59.5billionannually.Morethanathirdofthiscostcouldbeavoidedifbettersoftwaretestingwasperformed.Aprimarypurposefortestingistodetectsoftwarefailuressothatdefectsmaybeuncoveredandcorrected.Thisisanon-trivialpursuit.Testingcannotestablishthataproductfunctionsproperlyunderallconditionsbutcanonlyestablishthatitdoesnotfunctionproperlyunderspecificconditions.
Thescopeofsoftwaretestingoftenincludesexaminationofcodeaswellasexecutionofthatcodeinvariousenvironmentsandconditionsaswellasexaminingtheaspectsofcode:
doesitdowhatitissupposedtodoanddowhatitneedstodo.Inthecurrentcultureofsoftwaredevelopment,atestingorganizationmaybeseparatefromthedevelopmentteam.Therearevariousrolesfortestingteammembers.Informationderivedfromsoftwaretestingmaybeusedtocorrecttheprocessbywhichsoftwareisdeveloped.
Introduction
Whenaprogramisimplementedtoprovideaconcreterepresentationofanalgorithm,thedevelopersofthisprogramarenaturallyconcernedwiththecorrectnessandperformanceoftheimplementation.Softwareengineersmustensurethattheirsoftwaresystemsachieveanappropriatelevelofquality.Softwareverificationistheprocessofensuringthataprogrammeetsitsintendedspecification[Kaneretal.,1993].
Onetechniquethatcanassistduringthespecification,design,andimplementationofasoftwaresystemissoftwareverificationthroughcorrectnessproof.Softwaretesting,ortheprocessofassessingthefunctionalityandcorrectnessofaprogramthroughexecutionoranalysis,isanotheralternativeforverifyingasoftwaresystem.AsnotedbyBowen,Hinchley,andGeller,softwaretestingcanbeappropriatelyusedinconjunctionwithcorrectnessproofsandothertypesofformalapproachesinordertodevelophighqualitysoftwaresystems[BowenandHinchley,1995,Geller,1978].Yet,itisalsopossibletousesoftwaretestingtechniquesinisolationfromprogramcorrectnessproofsorotherformalmethods.
Softwaretestingisnota“silverbullet”thatcanguaranteetheproductionofhighqualitysoftwaresystems.Whilea“correct”correctnessproofdemonstratesthatasoftwaresystem(whichexactlymeetsitsspecification)willalwaysoperateinagivenmanner,softwaretestingthatisnotfullyexhaustivecanonlysuggestthepresenceofflawsandcannotprovetheirabsence.Moreover,Kaneretal.havenotedthatitisimpossibletocompletelytestanapplicationbecause[Kaneretal.,1993]:
(1)thedomainofprograminputsistoolarge,
(2)therearetoomanypossibleinputpaths,and(3)designandspecificationissuesaredifficulttotest.Thefirstandsecondpointspresentobviouscomplicationsandthefinalpointhighlightsthedifficultyofdeterminingifthespecificationofaproblemsolutionandthedesignofitsimplementationarealsocorrect.
Toimprovequality.
Ascomputersandsoftwareareusedincriticalapplications,theoutcomeofabugcanbesevere.Bugscancausehugelosses.Bugsincriticalsystemshavecausedairplanecrashes,allowedspaceshuttlemissionstogoawry,haltedtradingonthestockmarket,andworse.Bugscankill.Bugscancausedisasters.Theso-calledyear2000(Y2K)bughasgivenbirthtoacottageindustryofconsultantsandprogrammingtoolsdedicatedtomakingsurethemodernworlddoesn'tcometoascreechinghaltonthefirstdayofthenextcentury.[Bugs]Inacomputerizedembeddedworld,thequalityandreliabilityofsoftwareisamatteroflifeanddeath.
Qualitymeanstheconformancetothespecifieddesignrequirement.Beingcorrect,theminimumrequirementofquality,meansperformingasrequiredunderspecifiedcircumstances.Debugging,anarrowviewofsoftwaretesting,isperformedheavilytofindoutdesigndefectsbytheprogrammer.Theimperfectionofhumannaturemakesitalmostimpossibletomakeamoderatelycomplexprogramcorrectthefirsttime.Findingtheproblemsandgetthemfixed[Kaner93],isthepurposeofdebugginginprogrammingphase.
ForVerification&Validation(V&V)
JustastopicVerificationandValidationindicated,anotherimportantpurposeoftestingisverificationandvalidation(V&V).Testingcanserveasmetrics.ItisheavilyusedasatoolintheV&Vprocess.Testerscanmakeclaimsbasedoninterpretationsofthetestingresults,whicheithertheproductworksundercertainsituations,oritdoesnotwork.Wecanalsocomparethequalityamongdifferentproductsunderthesamespecification,basedonresultsfromthesametest.
Wecannottestqualitydirectly,butwecantestrelatedfactorstomakequalityvisible.Qualityhasthreesetsoffactors--functionality,engineering,andadaptability.Thesethreesetsoffactorscanbethoughtofasdimensionsinthesoftwarequalityspace.Eachdimensionmaybebrokendownintoitscomponentfactorsandconsiderationsatsuccessivelylowerlevelsofdetail.Table1illustratessomeofthemostfrequentlycitedqualityconsiderations.
Table1-TypicalSoftwareQualityFactors[etzel88]
Functionality
(exteriorquality)
Engineering
(interiorquality)
Adaptability
(futurequality)
Correctness
Efficiency
Flexibility
Reliability
Testability
Reusability
Usability
Documentation
Maintainability
Integrity
Structure
Goodtestingprovidesmeasuresforallrelevantfactors.Theimportanceofanyparticularfactorvariesfromapplicationtoapplication.Anysystemwherehumanlivesareatstakemustplaceextremeemphasisonreliabilityandintegrity.Inthetypicalbusinesssystemusabilityandmaintainabilityarethekeyfactors,whileforaone-timescientificprogramneithermaybesignificant.Ourtesting,tobefullyeffective,mustbegearedtomeasuringeachrelevantfactorandthusforcingqualitytobecometangibleandvisible.[Hetzel88]Testswiththepurposeofvalidatingtheproductworksarenamedcleantests,orpositivetests.Thedrawbacksarethatitcanonlyvalidatethatthesoftwareworksforthespecifiedtestcases.Afinitenumberoftestscannotvalidatethatthesoftwareworksforallsituations.Onthecontrary,onlyonefailedtestissufficientenoughtoshowthatthesoftwaredoesnotwork.Dirtytests,ornegativetests,referstothetestsaimingatbreakingthesoftware,orshowingthatitdoesnotwork.Apieceofsoftwaremusthavesufficientexceptionhandlingcapabilitiestosurviveasignificantlevelofdirtytests.
Black-boxtesting
Theblack-boxapproachisatestingmethodinwhichtestdataarederivedfromthespecifiedfunctionalrequirementswithoutregardtothefinalprogramstructure.[Perry90]Itisalsotermeddata-driven,input/outputdriven[Myers79],orrequirements-based[Hetzel88]testing.Becauseonlythefunctionalityofthesoftwaremoduleisofconcern,black-boxtestingalsomainlyreferstofunctionaltesting--atestingmethodemphasizedonexecutingthefunctionsandexaminationoftheirinputandoutputdata.[Howden87]Thetestertreatsthesoftwareundertestasablackbox--onlytheinputs,outputsandspecificationarevisible,andthefunctionalityisdeterminedbyobservingtheoutputstocorrespondinginputs.Intesting,variousinputsareexercisedandtheoutputsarecomparedagainstspecificationtovalidatethecorrectness.Alltestcasesarederivedfromthespecification.Noimplementationdetailsofthecodeareconsidered.
White-boxtesting
Contrarytoblack-boxtesting,softwareisviewedasawhite-box,orglass-boxinwhite-boxtesting,asthestructureandflowofthesoftwareundertestarevisibletothetester.Testingplansaremadeaccordingtothedetailsofthesoftwareimplementation,suchasprogramminglanguage,logic,andstyles.Testcasesarederivedfromtheprogramstructure.White-boxtestingisalsocalledglass-boxtesting,logic-driventesting[Myers79]ordesign-basedtesting[Hetzel88].Therearemanytechniquesavailableinwhite-boxtesting,becausetheproblemofintractabilityiseasedbyspecificknowledgeandattentiononthestructureofthesoftwareundertest.
Conclusion
Softwaretestingisanart.Mostofthetestingmethodsandpracticesarenotverydiff
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