test_that("check_quantile detects problematic specification", {
  expect_error(check_quantiles(TRUE, 0.5))
  expect_error(check_quantiles(0.1, "b"))
  expect_error(check_quantiles(seq(0, 1, length.out = 2), 1))
  expect_error(check_quantiles(1, seq(0, 1, length.out = 3)))
  expect_error(check_quantiles(-0.1, 1))
  expect_error(check_quantiles(0.5, 2))
  expect_error(check_quantiles(0.5, 0.2))
  expect_no_error(check_quantiles(0.2, 0.7))
})