# Skip slow tests
skip_slow <- function(message = "Slow test skipped") {
  if (exists("run_slow_tests", envir = .GlobalEnv)) {
    if (!get("run_slow_tests", envir = .GlobalEnv)) {
      skip(message)
    }
  } else if (!identical(Sys.getenv("RUN_SLOW_TESTS"), "true")) {
    skip(message)
  }
}