Supportsoft Glossary

Unit Testing for Isolating and Validating Code Units

Unit testing is used to evaluate components of a software application at the lowest level. This evaluation is performed to check whether each unit of an application (or function, method, or class) behaves as intended when working independently of other parts of the application. Developers typically write unit tests when writing the actual code using a unit testing framework such as JUnit, NUnit, pytest or Jest. Unit tests run automatically and quickly, which makes it possible to identify defects early in the software development life cycle.

In addition to identifying defects, unit tests also improve the overall quality of the codebase. They can identify logic errors and ensure that new changes do not introduce regressions into the code. Unit tests are also the basis of test-driven development (TDD), a methodology in which unit tests are created before coding the code being tested. In addition, by having well-written unit tests, developers can refactor (update/optimise) the code with a higher degree of confidence that they will identify any issues in their unit tests.

Unit testing gives increased reliability and maintainability to the software application as well as provides a means of documenting how the code is expected to function for any future developer. Within a solid QA strategy, unit testing provides stable, predictable components that allow for an overall more reliable system.