CTAL-TAE treats testability as a non-functional characteristic that should ideally be designed into the SUT. One mechanism for improving testability is the use of system environment variables. Application parameters exposed through environment variables can be administratively changed to make automated testing easier by improving controllability, configuring specific behavior, or enabling suitable test conditions without modifying production logic. Deployment variables provide a similar capability before deployment. Internet provider restrictions are external constraints rather than an intentional SUT testability mechanism. Reducing or increasing the number of features does not intrinsically make the system easier to automate, and changing the operating system version is primarily an environmental or compatibility consideration. Therefore, system environment variables are the syllabus-supported mechanism that can deliberately be changed to improve automation support.
