The test suite covers every line, and the test-coverage workflow fails below 100%. The per-process steps of sim_template() are the internal functions init_worker(), attach_package(), and run_worker(), so they can be tested in the current process as well as on the cluster.
The test suite pins the Chapter 3 results printed in the book (3.141554 for pi and the twenty Cauchy scale estimates) and checks the package workers against the book’s sim_worker.R listings.