tests/testthat/test_thread_option.R

In bbuchsbaum/fmrireg: R package for the anlysis of fmri data

context("Thread configuration")

test_that(".onLoad sets thread count from option", {
  testthat::local_edition(3)
  skip_if_not_installed("RcppParallel")
  
  # Check if thread setting actually works on this platform
  old_threads <- RcppParallel::defaultNumThreads()
  test_threads <- ifelse(old_threads == 2, 3, 2)  # Pick a different value
  RcppParallel::setThreadOptions(numThreads = test_threads)
  if (RcppParallel::defaultNumThreads() == old_threads) {
    skip("RcppParallel thread setting not working on this platform")
  }
  # Restore original for the actual test
  RcppParallel::setThreadOptions(numThreads = old_threads)
  
  old_opt <- getOption("fmrireg.num_threads")
  on.exit({
    options(fmrireg.num_threads = old_opt)
    RcppParallel::setThreadOptions(numThreads = old_threads)
  })

  options(fmrireg.num_threads = 2)
  fmrireg:::.onLoad(NULL, NULL)
  expect_equal(RcppParallel::defaultNumThreads(), 2)
})

 test_that(".onLoad sets thread count from env var", {
   skip_if_not_installed("RcppParallel")
   
   # Check if thread setting actually works on this platform
   old_threads <- RcppParallel::defaultNumThreads()
   test_threads <- ifelse(old_threads == 3, 4, 3)  # Pick a different value
   RcppParallel::setThreadOptions(numThreads = test_threads)
   if (RcppParallel::defaultNumThreads() == old_threads) {
     skip("RcppParallel thread setting not working on this platform")
   }
   # Restore original for the actual test
   RcppParallel::setThreadOptions(numThreads = old_threads)
   
   old_env <- Sys.getenv("FMRIREG_NUM_THREADS", unset = NA)
   on.exit({
     if (is.na(old_env)) Sys.unsetenv("FMRIREG_NUM_THREADS") else Sys.setenv(FMRIREG_NUM_THREADS = old_env)
     RcppParallel::setThreadOptions(numThreads = old_threads)
   })

   Sys.setenv(FMRIREG_NUM_THREADS = 3)
   options(fmrireg.num_threads = NULL)
   fmrireg:::.onLoad(NULL, NULL)
   expect_equal(RcppParallel::defaultNumThreads(), 3)
 })