Discover Testmark, a Markdown convention for test fixtures and data, in this 19-minute conference talk. Learn how to annotate code blocks in Markdown for easy loading into programs, making it ideal for test fixtures and executable examples. Explore the syntax, multi-language libraries, and real-world applications of Testmark. Gain insights into its impact on projects and its extensions for blackbox testing of executables. Understand how Testmark can help keep examples and documentation up-to-date while providing a format compatible across various programming languages.