This document discusses the testing challenges faced by the large and decentralized ACE open source project. It outlines the 4 step policy ACE developed using Coverity Test Advisor to prioritize testing efforts and enforce accountability. This included filtering rules to identify important code to test, analyzing untested code against the rules, and reducing the number of test violations from over 275,000 to around 2,588. Weekly Coverity scans help enforce the policy by identifying new issues for developers to resolve.