FitNesse

FitNesse is an open-source, wiki-based acceptance testing framework that combines a collaborative wiki interface with the FIT and Slim testing approaches. It enables executable documentation by letting both technical and non-technical stakeholders contribute tests describing expected system behavior in a readable, tabular form.

In FitNesse, tests are authored on pages as tables. The tables express inputs, actions, and expected results, and are interpreted by fixtures—code written in the language of the system under test, typically Java or .NET. The FitNesse server runs the wiki and test pages, rendering pages with navigation, version history, and search. When tests are executed, results are shown on the page and can be integrated into continuous integration pipelines or exported for reporting.

Key features include a built-in wiki interface, support for various table types (such as decision tables, action tables, and query tables), and extensibility through fixtures and plugins. It emphasizes living documentation: the tests double as specification and verification, helping teams keep documentation up to date as the product evolves. Reports and historical results aid traceability over time.

FitNesse is commonly used for acceptance testing and ATDD, fostering collaboration among developers, testers, and domain experts. It originated as an open-source project in the early 2000s and has evolved with the Slim engine to improve readability and performance. It runs cross-platform on Java and can be deployed as a standalone server or within a servlet container, with fixture code adapted to the host language.