test_that("units_per_unit", {
  expect_identical(dtt_units_per_unit(), 86400)
  expect_identical(dtt_units_per_unit("hours"), 24)
  expect_identical(dtt_units_per_unit("minutes", "seconds"), 1 / 60)
  expect_equal(
    dtt_units_per_unit("days", "months"),
    30.41667,
    tolerance = 1e-06
  )
})

test_that("adjust_units", {
  expect_identical(dtt_adjust_units(1), 1)
  expect_identical(dtt_adjust_units(1, "minutes"), 60)
  expect_identical(dtt_adjust_units(1, to = "minutes"), 1 / 60)
  expect_identical(dtt_adjust_units(1L, to = "minutes"), 1 / 60)
  expect_identical(dtt_adjust_units(1.12, "minutes"), 67.2)
  expect_identical(dtt_adjust_units(c(1, 1.12), "minutes"), c(60, 67.2))
})

test_that("NA", {
  expect_true(is.na(NA_POSIXct_))
  expect_true(is.POSIXct(NA_POSIXct_))
  expect_false(is.Date(NA_POSIXct_))
  expect_true(is.na(NA_Date_))
  expect_true(is.Date(NA_Date_))
  expect_false(is.POSIXct(NA_Date_))
  expect_true(is.na(NA_hms_))
  expect_false(is.Date(NA_hms_))
  expect_false(is.POSIXct(NA_hms_))
})

test_that("c.POSIXct", {
  expect_equal(
    c(as.POSIXct("2001-01-01")),
    as.POSIXct("2001-01-01"),
    ignore_attr = TRUE
  )
})

test_that("c.hms", {
  expect_identical(c(hms::as_hms("00:00:00")), hms::as_hms("00:00:00"))
})