> System under test (SUT) refers to a system that is being tested for correct operation. [^wk1] [^wk1]: [System under test (wikipedia)](https://en.wikipedia.org/wiki/System_under_test) ## The scope of the SUT The word "system" is often used to to imply the entire software application or workload but in this context it does not prescribe any level of scope, small or large. The SUT could be as small as a single function in a code module or an entire application.