Chapter 9 Compatibility Testing.docx

Chapter 9 Compatibility Testing.docx

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Chapter9CompatibilityTesting

Chapter9.CompatibilityTesting

INTHISCHAPTER

∙CompatibilityTestingOverview

∙PlatformandApplicationVersions

∙StandardsandGuidelines

∙DataSharingCompatibility

InChapter8,"ConfigurationTesting,"youlearnedabouthardwareconfigurationtestingandhowtoassurethatsoftwareworksproperlywiththehardwareitwasdesignedtorunonandconnectwith.Thischapterdealswithasimilarareaofinteractiontestingcheckingthatyoursoftwareoperatescorrectlywithothersoftware.

Testingwhetheroneprogramplayswellwithothershasbecomeincreasinglyimportantasconsumersdemandtheabilitytosharedataamongprogramsofdifferenttypesandfromdifferentvendorsandtakeadvantageoftheabilitytorunmultipleprogramsatonce.

Itusedtobethataprogramcouldbedevelopedasastandaloneapplication.Itwouldberuninaknown,understood,benignenvironment,isolatedfromanythingthatcouldcorruptit.Today,thatprogramlikelyneedstoimportandexportdatatootherprograms,runwithdifferentoperatingsystemsandWebbrowsers,andinteroperatewithothersoftwarebeingrunsimultaneouslyonthesamehardware.Thejobofsoftwarecompatibilitytestingistomakesurethatthisinteractionworksasuserswouldexpect.

Thehighlightsofthischapterinclude

∙Whatitmeansforsoftwaretobecompatible

∙Howstandardsdefinecompatibility

∙Whatplatformsareandwhattheymeanforcompatibility

∙Whybeingabletotransferdataamongsoftwareapplicationsisthekeytocompatibility

CompatibilityTestingOverview

Softwarecompatibilitytestingmeanscheckingthatyoursoftwareinteractswithandsharesinformationcorrectlywithothersoftware.ThisinteractioncouldoccurbetweentwoprogramssimultaneouslyrunningonthesamecomputerorevenondifferentcomputersconnectedthroughtheInternetthousandsofmilesapart.Theinteractioncouldalsobeassimpleassavingdatatoafloppydiskandhand-carryingittoanothercomputeracrosstheroom.

Examplesofcompatiblesoftwareare

∙Cuttingtextfromawebpageandpastingitintoadocumentopenedinyourwordprocessor

∙Savingaccountingdatafromonespreadsheetprogramandthenloadingitintoacompletelydifferentspreadsheetprogram

∙Havingphotographtouchupsoftwareworkcorrectlyondifferentversionsofthesameoperatingsystem

∙Havingyourwordprocessorloadinthenamesandaddressesfromyourcontactmanagementprogramandprintoutpersonalizedinvitationsandenvelopes

∙Upgradingtoanewdatabaseprogramandhavingallyourexistingdatabasesloadinandworkjustastheydidwiththeoldprogram

Whatcompatibilitymeansforyoursoftwaredependsonwhatyourteamdecidestospecifyandwhatlevelsofcompatibilityarerequiredbythesystemthatyoursoftwarewillrunon.Softwareforastandalonemedicaldevicethatrunsitsownoperatingsystem,storesitsdataonitsownmemorycartridges,anddoesn'tconnecttoanyotherdevicewouldhavenocompatibilityconsiderations.However,thefifthversionofawordprocessor（seeFigure9.1）thatreadsandwritesdifferentfilesfromotherwordprocessors,allowsmultiusereditingovertheInternet,andsupportsinclusionofembeddedpicturesandspreadsheetsfromvariousapplicationshasamultitudeofcompatibilityconsiderations.

Figure9.1.Compatibilityacrossdifferentsoftwareapplicationscanquicklybecomeverycomplicated.

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Ifyou'reassignedthetaskofperformingsoftwarecompatibilitytestingonanewpieceofsoftware,you'llneedtogettheanswerstoafewquestions:

∙Whatotherplatforms（operatingsystem,webbrowser,orotheroperatingenvironment）andotherapplicationsoftwareisyoursoftwaredesignedtobecompatiblewith?

Ifthesoftwareyou'retestingisaplatform,whatapplicationsaredesignedtorununderit?

∙Whatcompatibilitystandardsorguidelinesshouldbefollowedthatdefinehowyoursoftwareshouldinteractwithothersoftware?

∙Whattypesofdatawillyoursoftwareusetointeractandshareinformationwithotherplatformsandsoftware?

Gainingtheanswerstothesequestionsisbasicstatictestingbothblack-boxandwhite-box.Itinvolvesthoroughlyanalyzingthespecificationfortheproductandanysupportingspecifications.Itcouldalsoentaildiscussionswiththeprogrammersandpossiblyclosereviewofthecodetoassurethatalllinkstoandfromyoursoftwareareidentified.Therestofthischapterdiscussesthesequestionsinmoredetail.

PlatformandApplicationVersions

Selectingthetargetplatformsorthecompatibleapplicationsisreallyaprogrammanagementoramarketingtask.Someonewho'sveryfamiliarwiththecustomerbasewilldecidewhetheryoursoftwareistobedesignedforaspecificoperatingsystem,webbrowser,orsomeotherplatform.They'llalsoidentifytheversionorversionsthatthesoftwareneedstobecompatiblewith.Forexample,you'veprobablyseennoticessuchastheseonsoftwarepackagesorstartupscreens:

WorksbestwithAOL9.0

RequiresWindowsXPorgreater

ForusewithLinux2.6.10

Thisinformationispartofthespecificationandtellsthedevelopmentandtestteamswhatthey'reaimingfor.Eachplatformhasitsowndevelopmentcriteriaandit'simportant,fromaprojectmanagementstandpoint,tomakethisplatformlistassmallaspossiblebutstillfillthecustomer'sneeds.

BackwardandForwardCompatibility

Twotermsyou'llhearregardingcompatibilitytestingarebackwardcompatibleandforwardcompatible.Ifsomethingisbackwardcompatible,itwillworkwithpreviousversionsofthesoftware.Ifsomethingisforwardcompatible,itwillworkwithfutureversionsofthesoftware.

Thesimplestdemonstrationofbackwardandforwardcompatibilityiswitha.txtortextfile.AsshowninFigure9.2,atextfilecreatedusingNotepad98runningunderWindows98isbackwardcompatibleallthewaybacktoMS-DOS1.0.It'salsoforwardcompatibletoWindowsXPservicepack2andlikelywillbebeyondthat.

Figure9.2.Backwardandforwardcompatibilitydefinewhatversionswillworkwithyoursoftwareordatafiles.

NOTE

It'snotarequirementthatallsoftwareorfilesbebackwardorforwardcompatible.That'saproductfeaturedecisionyoursoftwaredesignersneedtomake.Youshould,though,provideinputonhowmuchtestingwillberequiredtocheckforwardandbackwardcompatibilityforthesoftware.

TheImpactofTestingMultipleVersions

Testingthatmultipleversionsofplatformsandsoftwareapplicationsworkproperlywitheachothercanbeahugetask.Considerthesituationofhavingtocompatibilitytestanewversionofapopularoperatingsystem.Theprogrammershavemadenumerousbugfixesandperformanceimprovementsandhaveaddedmanynewfeaturestothecode.TherecouldbetensorhundredsofthousandsofexistingprogramsforthecurrentversionsoftheOS.Theproject'sgoalistobe100percentcompatiblewiththem.SeeFigure9.3.

Figure9.3.Ifyoucompatibilitytestanewplatform,youmustcheckthatexistingsoftwareapplicationsworkcorrectlywithit.

[Viewfullsizeimage]

Thisisabigjob,butit'sjustanotherexampleofhowequivalencepartitioningcanbeappliedtoreducetheamountofwork.

NOTE

Tobeginthetaskofcompatibilitytesting,youneedtoequivalencepartitionallthepossiblesoftwarecombinationsintothesmallest,effectivesetthatverifiesthatyoursoftwareinteractsproperlywithothersoftware.

Inshort,youcan'ttestallthethousandsofsoftwareprogramsonyouroperatingsystem,soyouneedtodecidewhichonesarethemostimportanttotest.Thekeywordisimportant.Thecriteriathatmightgointodecidingwhatprogramstochoosecouldbe

∙Popularity.Usesalesdatatoselectthetop100or1,000mostpopularprograms.

∙Age.Youmightwanttoselectprogramsandversionsthatarelessthanthreeyearsold.

∙Type.Breakthesoftwareworldintotypessuchaspainting,writing,accounting,databases,communications,andsoon.Selectsoftwarefromeachcategoryfortesting.

∙Manufacturer.Anothercriteriawouldbetopicksoftwarebasedonthecompanythatcreatedit.

Justasinhardwareconfigurationtesting,thereisnoright"textbook"answer.Youandyourteamwillneedtodecidewhatmattersmostandthenusethatcriteriatocreateequivalencepartitionsofthesoftwareyouneedtotestwith.

Thepreviousexampledealtwithcompatibilitytestinganewoperatingsystemplatform.Thesameissuesapplytotestinganewapplication（seeFigure9.4）.Youneedtodecidewhatplatformversionsyoushouldtestyoursoftwareonandwhatothersoftwareapplicationsyoushouldtestyoursoftwarewith.

Figure9.4.Compatibilitytestinganewapplicationmayrequireyoutotestitonmultipleplatformsandwithmultipleapplications.

StandardsandGuidelines

Sofarinthischapteryou'velearnedaboutselectingthesoftwarethatyou'llcompatibilitytestwithyourprogram.Now,it'stimetolookathowyou'llapproachtheactualtesting.Yourfirststopshouldberesearchingtheexistingstandardsandguidelinesthatmightapplytoyoursoftwareortheplatform.

Therearereallytwolevelsoftheserequirements:

high-levelandlow-level.Itmaybeamisnomertorefertothemashighandlow,butinasense,that'sreallywhattheyare.High-levelstandardsaretheonesthatguideyourproduct'sgeneraloperation,itslookandfeel,itssupportedfeatures,andsoon.Low-levelstandardsarethenitty-grittydetails,suchasthefileformatsandthenetworkcommunicationsprotocols.Bothareimportantandbothneedtobetestedtoassurecompatibility.

High-LevelStandardsandGuidelines

WillyoursoftwarerununderWind