Software testing is a process in which a software system's dynamic behaviours are observed and analysed so that the system's properties can be inferred from the information revealed by test executions. While the existing theories of software testing might be adequate in describing the testing of sequential systems, they are not capable to describe the testing of concurrent systems that can exhibit different behaviours on the same test case due to non-determinism and concurrency. In our previous work, we proposed a theoretical framework that provides a unified foundation to study all testing methods for both sequential and concurrent systems. The main results of the framework include a formal definition of the notion and a set of the desirable properties of an observation scheme. In this paper, we provide several constructions of observation schemes that have direct implications in current software testing practice. We also study the properties of the constructions.
