run tests in parallel on the jvm

Question

Goals

• deterministic -- calling quick-check with parallel opts gives the same answer as without
  -- we have to give up some determinism though, because I don't think we could reasonably
  say that the {{reporter-fn}} will be called the same way every time, or even that
  the {{:num-tests}} value returned should always be the same
• does the best possible thing on the jvm w.r.t. things hanging
• is it necessary to have some sort of dynamic var with a thread id or something similar,
  so users can use it to coordinate usage of global resources? alternatively they could
  use a {{ThreadLocal}} by hand, or a pool

Issues

• Is this really worth it? The downside is it makes the API and impl of {{quick-check}} more complex, and arguably most use cases could be served by calling {{quick-check}} multiple times from separate threads; would a generic test-suite parallelizer do the job for most people?

Answer 1

Reference: https://clojure.atlassian.net/browse/TCHECK-115 (reported by gfredericks)