Opunit: Sanity Checks for Computing Environments Computing environments, including virtual machines and containers, are essential components of modern software engineering infrastructure. Despite emerging tools that support the creation and configuration of computing environments, they are limited in testing and validating the construction of these environments. Furthermore, professionals and students new to these concepts, lack feedback on their construction efforts. In this paper, we argue that the design of environment testing tools should fundamentally support asserting essential properties, such as reachability and availability, in order to maximize usability and utility. We present opunit, an environment testing tool that supports assertion of these properties. We describe properties students failed to check when testing computing environments, which guided the design of opunit. Finally, we share our early experiences with using opunit in the classroom to support education and training in configuration of computing environments.

Charting a Course Through Uncertain Environments: SEA Uses Past Problems to Avoid Future Failures A common problem for developers is applications exhibiting new bugs after deployment. Many of these bugs can be traced to unexpected network, operating system, and file system differences that cause program executions that were successful in a development environment to fail once deployed. Preventing these bugs is difficult because it is impractical to test an application in every environment. Enter Simulating Environmental Anomalies (SEA), a technique that utilizes evidence of one applicationu0027s failure in a given environment to generate tests that can be applied to other applications, to see whether they suffer from analogous faults. In SEA, models of unusual properties extracted from interactions between an application, A, and its environment guide simulations of another application, B, running in the anomalous environment. This reveals faults B may experience in this environment without the expense of deployment. By accumulating these anomalies, applications can be tested against an increasing set of problematic conditions. We implemented a tool called CrashSimulator, which uses SEA, and evaluated it against Linux applications selected from coreutils and the Debian popularity contest. Our tests found a total of 63 bugs in 31 applications with effects including hangs, crashes, data loss, and remote denial of service conditions.