Based On Commercial Off The Shelf Test Driven Of Software Lifecycle Model

The purpose of this paper is to describe a model of COTS Based SoftwareLifecycle. TVCM (Test Driven V-Waterfall Lifecycle of COTS Based SystemLifecycle Model) based on V-Waterfall Lifecycle, using the way of test driven to ensurethe quality of COTS Based Software System.Current major organizations and large-scale systems usually use some COTS(commercial off the shelf) components. However, Traditional software lifecycle modelcreated base traditional software lifecycle not completely suit COTS based systemdevelopment and maintenance process. How to limit the risk of COTS productsevolution and respect the lake of information of COTS products is the challenge ofCOTS based system developer (application developer).COTS (commercial off the shelf) Based System development and maintenancehas two mainly problems application developer must deal with:First is Lack of information. COTS products provide by the venders. Only provideexample of how to use it, and user manual. Application developer may not enoughfamiliar with the COTS products (Function, performance, etc).Second is COTS components future not under the application developer's control.New versions or releases of COTS products are brought to the market frequently.Application developer has little or no control over the evolution of the system .Except the above two main problems, there are also many other problems mayhappened in the development period. For example, COTS products might work well ina certain application environment and exhibit failures in another .The major obstacles to the taking up of the COTS based system are nottechnological, but relate to the process Traditional lifecycle model not completely suitthe COTS based system development and maintenance. New characteristics introducenew problems. Such as evaluation of COTS component must begin at early stage of thesystem development, but at this stage requirements are ambiguous yet. And COTSproducts volatility maybe happened at any stage of the lifecycle. Development processmust adapt to change as soon as possible. So the model introduced, aim at COTS characteristics. Our model figures out, dotest first is the better way to confirm the requirements and information of COTSproduces. Additional tests have to be done in order to obtain sufficient confidence thatthe COTS products will behave as intended also in the new application environment.While new software development models continue to be popular with practitioners,the V model has gained particularly wide acceptance.The SVW lifecycle is depicting the basic sequence of development and testingactivities. The SVW model is valuable because it emphasizes the existence of severallevels of testing and depicts the way each relates to a different development phase. Bythis advancement software quality assurance is achieved.TVCM (Test Driven V-Waterfall Lifecycle of COTS Based System LifecycleModel) is being designed specifically to TDD (Test Driven Development) lifecyclehighlight in the information obtain and confirm when you development COTS Basedlarger system.We develop this model when we study other base COTS model and TDD. Wefound that test driven development is the best way to overcome COTS products'relatively immature.During recent years, TDD is accepted by more and more developers. Test DrivenDevelopment (TDD) is a cornerstone of eXtreme Programming (XP). However, thebenefits of practicing TDD are not limited to XP. It regards testing as a continuousprocess to be carried out as an integral part of developing code. TDD deals with unittests written by the developer to ensure that his or her code works fine and stays thatway. This way it can be ensured, the code guarantee the user's requirements if and onlyif the test cases are based on requirements.In COTS Based System most code are the glue code and wrapper code, most ofthem deal with multifarious interfaces, or configuration files. This code has clear inputand output data. So when we finished test code, we can easily obtain the expected codes.TDD can deal with the requirements change as soon as possible. This characteristic isideal for the COTS products'volatility. In the non-code phase, test is also the better wayof reviews the requirements, familiar system, and assessment COTS products. We alsocall this method: Test driven. In this model we use this idea driving the development ofCOTS based software.WCTM(Based on W-Waterfall Lifecycle of COTS Test Driven of System Lifecycle Model) at the moment is composed of five related phrases:1, Requirements Analysis, System Test Plan and COTS AssessmentAt an extremely early stage, requirements are generally less than completelydefined and often provide only the most general guidance to the developer. But duringCOTS based system development process, developer needs to evaluate the candidateCOTS products at an early stage. And COTS characteristic also influence requirementsdecisions. COTS evaluation process is inextricably linked to requirements definition. Inthis model the requirements evolve with the test design and COTS selection.2, COTS Selection Test, Integration Test Design and COTS TailoringDuring this phrase, first step is test candidate COTS products which we pick up ascandidate, and then design integration test.In our model using test method include performance test and functional test forconfirm COTS products candidate list. The results of COTS selection test will be aconfirmation that the qualified candidates perform appropriately in system context.During this stage, we have already decided which COTS products will be used inthe system. Next step is integrating them into the system. This action is also driven bytest: integration test.The phase of integration test design (test plan and test case) is the phase familiarwith COTS products interface and configure that will be used.Then COTS tailoring start base on the integration test plan and test case.3, Detail Design, Unit Test Design, Glue Code/Wrapper Code Development andUnit TestDetail design pays attention to the detail of glue code and wrapper code part. Inthis part, TDD idea is tailor made for the development work.TDD has two obvious differences with normal methodology. One is to test first. Inour model all the main actions are to test first to guarantee quality without question inthis phase. But in this phase test first not means test plan or test case first. It means testcode to be written first. Another is development period shorter than the tradition method.This characteristic can preferably suit unexpected requirements change. COTS productsare updated frequently in market. So in any stage of lifecycle COTS products evaluationmaybe happened. A fast adjustment to the demanding change is very important to theCOTS based system development. In our model, for using the TDD method we regardglue code and wrapper code as some units. Each unit corresponds to one or more test case.4, Integration Test, System Test and User Acceptance TestThis phase is almost same to the tradition V model. There are two problems weshould consider in this phase:First, we must monitor the market for the COTS products evolution happening. Ifevaluation happened, our phase have to partly turn back to the assessment stage.Second, the granularity of those tests must be cared by application developer.5, Maintenance and Regression TestSystem maintenance is set of activities that are performed to keep a systemoperational as software changes after the system has been fielded. In this stage,regression test is performed for testing system that has not regressed. We can reuse thetest case in the prior stage.In this paper we described a model of COTS component based system lifecycle.WCTM is based on traditional V model, and using the TDD idea. In this model allactions are driven by test. Using this model you must make sure what you want to dofirst and then do it with clear purpose. By this way we can overcome the informationambiguity and volatility of COTS products.This model is a standard model for large-scale systems. If the system is smaller,some tests could be omitted such as integration test and system test can be incorporatedtogether. Also some documents can be incorporated such as test analysis and testspecification.In this model writing test analysis is a difficult task. And it is also the key task.