Dillon: CSE470: SYSTEM INTEGRATION 1 Build Plan l Development or integration strategies l Decide the order in which components of the system will be developed

Dillon: CSE470: SYSTEM INTEGRATION 2 Uses Graph Play Game Collect Cards Determine Winner Play Hand Deal Announce Winner Compare Hands Get Hand Value

Dillon: CSE470: SYSTEM INTEGRATION 3 Common build strategies l Big Bang »All coding precedes all integration l Bottom Up »Start at low-level utility modules l Top Down »Start at high-level control modules l Incremental/Sandwich »Integrate control modules top down and utility modules bottom up

Dillon: CSE470: SYSTEM INTEGRATION 4 Big Bang Integration l Advantages »No need to write stubs or drivers l Disadvantages »Difficult to identify units causing errors »Critical modules receive no extra testing »Major design flaws are discovered very late »No flexibility in scheduling

Dillon: CSE470: SYSTEM INTEGRATION 5 Bottom Up Integration l Implement a module l Implement a test driver »often a quick prototype l Execute tests l Implement and test all modules called by the driver (prototype), one at a time

Dillon: CSE470: SYSTEM INTEGRATION 6 Bottom Up Integration (cont.) l Replace the test driver (prototype) with its implementation l Implement a test driver for the new module l Repeat until all modules are integrated

Dillon: CSE470: SYSTEM INTEGRATION 7 Bottom Up Integration l Advantages »no need to write stubs »low level utilities are well tested »high-level (often simple) drivers are not as well tested l Disadvantages »not all low level utilities are important »emphasis on low level functionality »major design flaws are dis- covered late

Dillon: CSE470: SYSTEM INTEGRATION 8 Top Down Integration l Implement highest level component l Create stubs for called component l Test the component with the stubs l Implement and test stubs one by one »use stubs for any called components l Repeat until all stubs are implemented

Dillon: CSE470: SYSTEM INTEGRATION 9 Top Down Integration l Advantages »no need to write drivers »high-level drivers are well tested »unimportant low- level utilities are not as well tested l Disadvantages »important low- level utilities are not as well tested »simple high-level drivers may not need the extra testing

Dillon: CSE470: SYSTEM INTEGRATION 10 Incremental Top Down Integration l Identify most important path through the uses graph »implement and test the highest module in the path –creating drivers and stubs as necessary »select the next module on that path »repeat until the path is done

Dillon: CSE470: SYSTEM INTEGRATION 11 Incremental Top Down Integration (cont.) l Select next most important path and follow the same process l Repeat until all paths have been implemented l Paths do not have to start at the root or end with leaves

Dillon: CSE470: SYSTEM INTEGRATION 12 Incremental Top Down Integration l Advantages »test the most important functionality first »easy to isolate errors »find major design flaws early »have an incomplete but “working” system early –good for morale, visibility, early assessment »minimizes the need for drivers and stubs

Dillon: CSE470: SYSTEM INTEGRATION 13 Developing an incremental build plan l Identify most important paths through the uses graph »most used functionality; centrality »complex component that plays a key role l Save “frills” for later paths l Produce something that works early »add features incrementally for easier testing and debugging