Explore a 17-minute conference talk from Dyalog '24 that introduces ullu, a rigorous testing framework designed for Dyalog APL. Learn about the framework's mission to achieve comprehensive source code coverage and verify the reliability of Dyalog APL primitives. Discover the quality assurance testing processes, supported versions and platforms, and the detailed test-writing methodology employed by ullu. Follow along as the presentation covers model functions for primitives, testing strategies across different argument types, and current code coverage achievements. Gain insights into the future development plans and find out how to contribute to this open-source testing framework available on GitHub.