A new Jepsen release, 0.3.10, is now available on GitHub and Clojars. This release is aimed at controllable entropy and support for running Jepsen inside Antithesis: a deterministic simulation testing environment. A new supporting library, jepsen.generator, provides the current generator system along with jepsen.random: a new namespace for pluggable random value generation. Jepsen uses these RNGs throughout, which makes it possible to run a test with a deterministic seed, or to source entropy from an external system, like Antithesis. The jepsen.antithesis library provides additional support for assertions, randomness, and lifecycle operations, plus wrappers for clients and checkers.

Also, this release introduces a new kind of visualization: op color plots, which show operations over time with different user-defined colors. This is particularly helpful for getting a feeling for “when did we lose data?” or “did only read-only queries succeed during a partition?”