test_that("using_envvar() validates input properly", {
  expect_error(using_envvar(c("HOME", "CI")), class = "arg_not_scalar_string")
  expect_error(using_envvar(NULL), class = "arg_not_scalar_string")
  expect_error(using_envvar(NA_character_), class = "arg_not_scalar_string")

  expect_error(
    using_envvar("HOME", c("x", "y")),
    class = "arg_not_scalar_string"
  )
  expect_error(
    using_envvar("HOME", NA_character_),
    class = "arg_not_scalar_string"
  )
})

test_that("get_envvar() works as expected", {
  random_string <- paste0(sample(c(letters, LETTERS), 10), collapse = "")

  withr::with_envvar(new = c("CHECKENV_TEST_SET" = random_string), {
    expect_equal(get_envvar("CHECKENV_TEST_SET"), random_string)
  })

  withr::with_envvar(new = c("CHECKENV_TEST_NOTSET" = NA), {
    expect_true(is.na(get_envvar("CHECKENV_TEST_NOTSET")))
  })
})


test_that("using_envvar() works as expected", {
  random_string <- paste0(sample(c(letters, LETTERS), 10), collapse = "")

  withr::with_envvar(new = c("CHECKENV_TEST_SET" = random_string), {
    expect_true(using_envvar("CHECKENV_TEST_SET"))
    expect_true(using_envvar("CHECKENV_TEST_SET", value = random_string))
    expect_false(using_envvar("CHECKENV_TEST_SET", value = "notthis"))
  })

  withr::with_envvar(new = c("CHECKENV_TEST_NOTSET" = NA), {
    expect_false(using_envvar("CHECKENV_TEST_NOTSET"))
  })
})