SLASHING CI WAIT TIMES: HOW PINTEREST CUT ANDROID TESTING BUILD TIMES BY 36%+

Summary from the TLDR Dev newsletter

Pinterest reduced Android testing build times by over 36% by implementing a runtime-aware sharding mechanism. This in-house system, called PinTestLab, uses historical test duration and stability data from Pinterest's test management system, Metro, to distribute tests across shards running on EC2-hosted emulators. The algorithm assigns tests to emulators projected to finish earliest by prioritizing equal wall-time over equal test counts.