What does "unit test" mean in programming?

unit test is one of the most common terms in software development. This guide explains what it means, how it is used in practice, and why it matters, with real examples from the developer world.

Definition

A test that verifies a single, isolated unit of code (a function, method, or class) in isolation from other components. Unit tests are fast, easy to write, and catch bugs early in development.

Example

"Write a unit test for the calculateDiscount function to cover the edge cases."

Related terms

integration test
end-to-end test
assertion
mock
coverage

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