System under test explained

System under test (SUT) refers to a system that is being tested for correct operation. According to ISTQB it is the test object.^{[1] [2] [3]}

From a unit testing perspective, the system under test represents all of the classes in a test that are not predefined pieces of code like stubs or even mocks. Each one of this can have its own configuration (a name and a version), making it scalable for a series of tests to get more and more precise, according to the quantity of quality of the system in test.

ISO/IEC/IEEE 29119 defines SUT within a standardized vocabulary and test-process framework.^[4]

See also

• Device under test
• Test harness

External links

• Test Procedure for §170.314(c) Clinical quality measures

Notes and References

1. Web site: ISTQB Glossary. glossary.istqb.org. 2018-02-05.
2. Web site: Don't Stub the System Under Test. robots.thoughtbot.com. 22 November 2013 . 2018-02-05.
3. Web site: SUT (system under test). www.itwissen.info. de. 2021-02-24.
4. Web site: 2022 . ISO/IEC/IEEE 29119-1:2022 — Software testing — Part 1: Concepts and definitions . 17 September 2025 . ISO/IEC/IEEE.