test_that("empty input returns a list, but after the index size check", {
  i <- new_date()

  expect_equal(pslide_period(list(integer(), integer()), i, "day", ~.x), list())
  expect_equal(pslide_period(list(integer(), 1), i, "day", ~.x), list())
  expect_equal(pslide_period(list(1, integer()), i, "day", ~.x), list())

  i <- new_date(0)

  expect_snapshot({
    (expect_error(pslide_period(list(integer(), integer()), i, "day", ~.x), class = "slider_error_index_incompatible_size"))
  })
})

test_that("completely empty input returns a list", {
  expect_equal(pslide_period(list(), new_date(), "day", ~.x), list())
})

test_that("empty input works with `.complete = TRUE` (#111)", {
  expect_equal(pslide_period(list(integer(), integer()), new_date(), "year", ~.x, .complete = TRUE), list())
})