Bringing Modern Unit Testing Techniques to Sensornets

Unit testing, an important facet of software quality assurance, is underappreciated by wireless sensor network (sensornet) developers. This is likely because our tools lag behind the rest of the computing field. As a remedy, we present a new framework that enables modern unit testing techniques in sensornets. Although the framework takes a holistic approach to unit testing, its novelty lies mainly in two aspects. First, to boost test development, it introduces embedded mock modules that automatically abstract out dependencies of tested code. Second, to automate test assessment, it provides embedded code coverage tools that identify untested control flow paths in the code. We demonstrate that in sensornets these features pose unique problems, solving which requires dedicated support from the compiler and operating system. However, the solutions have the potential to offer substantial benefits. In particular, they reduce the unit test development effort by a few factors compared to existing solutions. At the same time, they facilitate obtaining full code coverage, compared to merely 57--72% that can be achieved with integration tests. They also allow for intercepting and reporting many classes of runtime failures, thereby simplifying the diagnosis of software flaws. Finally, they enable fine-grained management of the quality of sensornet software.