test_that("Kernels", {
  expect_equal(truncated_kernel(-3:3 / 2), c(0, 1, 1, 1, 1, 1, 0))
  expect_equal(bartlett_kernel(-3:3 / 2), c(0, 0, 0.5, 1, 0.5, 0, 0))
  expect_equal(parzen_kernel(-3:3 / 2), c(0, 0, 0.25, 1, 0.25, 0, 0))
  expect_equal(tukey_hanning_kernel(-3:3 / 2), c(0, 0, 0.5, 1, 0.5, 0, 0))
  expect_equal(
    round(quadratic_spectral_kernel(-3:3 / 2), 4),
    c(-0.0857, 0.1379, 0.6869, 1, 0.6869, 0.1379, -0.0857)
  )
  expect_equal(round(daniell_kernel(-3:3 / 2), 4), c(0, 0, 0.6366, 1, 0.6366, 0, 0))
  expect_equal(flat_top_kernel(-3:3 / 2), c(0, 0.1, 0.6, 1, 0.6, 0.1, 0))
})

test_that("Adaptive Bandwidth", {
  expect_equal(round(adaptive_bandwidth(electricity, bartlett_kernel), 4), 69.3986)
})