Unit Test
A focused automated test of a small unit of behavior in isolation from most external dependencies.
Plain English
Check one small piece of logic quickly and precisely.
In context
Unit tests give fast localized feedback and commonly replace collaborators with controlled fakes when isolation improves the test.
Example
“The unit test verifies the retry delay calculation for the third attempt.”
When you'll hear this
- development
- continuous integration
- refactoring
Common misunderstanding
A unit test is defined by focused isolation and feedback rather than a specific function size or test framework.
Also known as
unit testingcomponent unit test
Commonly used by
Related terms
Updated: 2026-08-27
