A test stub is a test double that provides static values to the software under test.
A test stub provides canned answers to calls made during the test, usually not responding at all to anything outside what's programmed in for the test.1
A stub may be coded by hand, generated via a tool or be created as a dedicated part of a larger system such as a stub server or service.
Stubs differ from mock objects, which assert and verify interactions. Stubs only supply data.23
References
References
- Fowler, Martin (2007), Mocks Aren't Stubs (Online)
- Freeman, Steve; Pryce, Nat (2009). Growing Object-Oriented Software, Guided by Tests. Addison-Wesley. ISBN 978-0321503626.
- Fowler, Martin. "Mocks Aren't Stubs". martinfowler.com. Retrieved 2025-09-17.