Improving Testing with Quality Stubs

Many testers use stubs-simple code modules that simulate the behavior of much more complicated things. As components and their interfaces evolve, it is easy to overlook the need for associated stubs to evolve with them. Lee Clifford explains that the stubs Virgin Mobile previously used to simulate the functionality of third-party software were basic and static-simply returning hard-coded data values. While adequate, the stubs were difficult to maintain. So Virgin Mobile's testers decided to design, build, test, and deploy their own smart "quality stubs," not only for use by the test team but also for development and performance testing. The testers created fully configurable and programmable stubs that interface their systems to third-party products. The key advantage is that anyone in the test team can update the stubs with minimal cost and without the need to learn a programming language.

• The need for and value of quality stubs when testing
• The different types of stubs you may need
• How to build smart quality stubs that are first-class software tools