ISBN : 978-81-963532-2-3 (E-Book) 23 INTEGRATIONTESTING Theprimaryobjectiveofintegrationtestingistotestthemoduleinterfaces,i.e.therearenoerrors in the parameter passing, when one module invokes another module. During integrationtesting, different modules of a system are integrated in a planned manner using an integrationplan. The integration plan specifies the steps and the order in which modules are combined torealize the full system. After each integration step, the partially integrated system is tested. Animportant factor that guides the integration plan is the module dependency graph. The structurechart(ormoduledependencygraph)denotestheorderinwhichdifferentmodulescalleachother .Byexaminingthestructurechart theintegrationplancan bedeveloped. Integrationtestapproaches There are four types of integration testing approaches. Any one (or a mixture) of the followingapproachescanbeusedtodevelop arethefollowing: theintegrationtestplan.Thoseapproaches Bigbangapproach Bottom-upapproach Top-downapproach Mixed-approach Big-BangIntegrationTesting It is the simplest integration testing approach, where all the modules making up a system areintegrated in a single step. In simple words, all the modules of the system are simply put togetherandtested.However,thistechniqueispracticableonlyforverysmallsystems.Themainproblem with this approach is that once an error is found during the integration testing, it is verydifficult to localize the error as the error may potentially belong to any of the modules beingintegrated. Therefore, debugging errors reported during big bang integration testing are veryexpensive to fix. Bottom-UpIntegrationTesting In bottom-up testing, each subsystem is tested separately and then the full system is tested. Asubsystem might consist of many modules which communicate among each other through well-defined interfaces. The primary purpose of testing each subsystem is to test the interfaces amongvarious modules making up the subsystem. Both control and data interfaces are tested. 103 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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