# # custom skip helper that runs tests only on CI and not on local R CMD Checks
# 
# skip_local_run_ci <- function() {
#   ci <- Sys.getenv("CI")
#   if (identical(ci, "") || identical(ci, "false") || identical(ci, "0")) {
#     testthat::skip("Skipping: not on CI")
#   }
# }
# 
# # Usage 
# # skip_local_run_ci()
# # 
# # test_that("big model behaviour", {
# #   # heavy fits / large objects tested here
# # })