In this lates blog post we take a look how json-joy tests its RGA list CRDT implementation. json-joy implementation is highly optimized, and optimizations themselves lead to bugs. We use three different fuzzers to verify correctness of our list CRDT implementation:

A fuzzer which simulates two random users editing.

A fuzzer which simulates multiple random users editing.

And finally, a fuzzer which simulates whole JSON, including string CRDT and array CRDT operations, of multiple users concurrently editing a document.

Read more about how we fuzz test here.