FitNesse is an acceptance testing framework.
FitNesse is a wiki based testing framework and software development collaboration tool. It allows software teams to easily collaborate and define Acceptance Tests and to Run those tests and see the results.
FitNesse is authored in Java, and supports two types of test systems, known as fit-framework and Slim fitnesse-slim.
FitNesse test behavior is driven through the development and use of components called fixtures, which are typically coded by developers or QA engineers. Fixtures are required to build the domain-specific language in which testers can model tests. Through this level of indirection, many tests can be accessible to, and written by, non-technical users.
Although written with native Java in mind, FitNesse also supports test fixtures written in .net through the use of another open source project, fitsharp.