test_that("with_collate works and resets collate", {
  current <- Sys.getlocale("LC_COLLATE")
  new <- "C"
  with_collate(
    new,
    {
      expect_equal(new, Sys.getlocale("LC_COLLATE"))
    }
  )
  expect_equal(current, Sys.getlocale("LC_COLLATE"))
})

test_that("with_collate() and with_locale() set LC_COLLATE envvar (#179)", {
  en_US <- en_locale_or_skip()

  output <- callr::r(
    env = c(LC_COLLATE = "C"),
    args = list(en_US = en_US),
    function(en_US) {
      out <- withr::with_collate(en_US, sort(c("A", "a")))
      stopifnot(identical(Sys.getenv("LC_COLLATE"), "C"))
      out
    }
  )
  expect_equal(output, c("a", "A"))

  output <- callr::r(
    env = c(LC_COLLATE = "C"),
    args = list(en_US = en_US),
    function(en_US) {
      out <- withr::with_locale(c(LC_COLLATE = en_US), sort(c("A", "a")))
      stopifnot(identical(Sys.getenv("LC_COLLATE"), "C"))
      out
    }
  )
  expect_equal(output, c("a", "A"))
})