Unit 241 Integration Phase  The objective of this section is to introduce how the software product is realized from a set of programs, program units or modules. When you have read this section you will: ounderstand the importance of the object oriented design that leads to the modular programming and integration; oknow the difference between the unit testing and the integration testing.

Unit 242  During the integration phase, the various component modules are combined to build the software product. The modules may be integrated using top-down approach or bottom-up approach. Suppose the product is integrated bottom-up. If there is a major design fault, then it will show up late, necessitating an expensive rewrite. Conversely, if the modules are integrated top-down, then the lower level modules usually will not receive as thorough a testing as would be the case if the product were integrated bottom-up.  Integration testing, system testing and acceptance testing are integral part of Implementation Phase. What is Integration?

Unit 243  The purpose of integration testing is to check that the modules combine correctly to achieve a product that satisfies its requirements. During the integration testing, particular care must be paid to testing the module interfaces.  When integration testing is completed, system testing is performed. The functionality of the product as a whole (including the performance, security, robustness, safety, maintainability, scalability etc.) is checked against the specifications.  The final aspect of this phase is acceptance testing. The software is delivered to the client, who tests the software on the actual hardware using actual data, as opposed to test data (sample data used by the developers). A software product cannot be considered to satisfy its specifications until the product has passed its acceptance tests. What is Integration? (cont ’ d)

Unit 244 The Integrated Software  Here we see the integrated software of the project.  The name of the project is Bank.  The software is integrated with the Account.class, Customer.class and Bank.html.

Unit 245 Exercises 1.What is a bottom-up approach of integration? 2.What is a top-down approach of integration? 3.What are the advantages and disadvantages of the two approaches?