# Text-Runner > Test runner for text Text-Runner makes rich text executable. An example is the documentation you are reading right now. Text-Runner executes certain parts of it to verify that it correctly describes how Text-Runner works. Text-Runner allows you to - test your natural-language documentation - make your end-to-end tests completely human-readable prose - write computer programs in natural language There are no limitations on the type of text that TextRunner can execute. It can read and understand (if you tell it how) any form of plain text in any human language as well as complex data in tables, bullet point lists, or embedded images. This can be useful for things like - **agile documentation:** your documentation always matches the behavior of the product it describes - **[semantic versioning](http://semver.org):** know whether a product change affects documented behavior - **[readme-driven development](http://tom.preston-werner.com/2010/08/23/readme-driven-development.html):** documentation becomes your product prototype and drives the implementation More information about: - [how it works](../documentation/how-it-works.md) - [installation](../documentation/installation.md) - [built-in actions](../documentation/built-in-actions.md) - [user-defined actions](../documentation/user-defined-actions.md) - [external actions](../documentation/external-actions.md) - [questions and answers](../documentation/qna.md) - [related tools](../documentation/related-tools.md)