test_that('D&S examples page 218', {
  expect_equal(d_max(129.5, 120, 170), .189, tolerance = .01)           # pico
  expect_equal(d_max(1300, 1000, 1300), 1, tolerance = .01)             # modulus
  expect_equal(d_target(465.7, 400, 500, 600), 0.656, tolerance = .01)  # elongation
  expect_equal(d_target(68, 60, 67.5, 75), 0.932, tolerance = .01)      # hardness
})


test_that('correct values', {
  x <- seq(0, 1, length.out = 11)

  # ------------------------------------------------------------------------------
  # Expected results form original desirability package. See test-cases dir

  expect_equal(
    d_max(x, .1, .9),
    c(0, 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, 1, 1)
  )
  expect_equal(
    d_max(x, 0, 1),
    c(0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1)
  )
  expect_equal(
    d_max(x, .1, .9, 1/2),
    c(0, 0, 0.3536, 0.5, 0.6124, 0.7071, 0.7906, 0.866, 0.9354, 1, 1),
    tolerance = 0.1
  )
  expect_equal(
    d_max(x, .1, .9, 3),
    c(0, 0, 0.002, 0.0156, 0.0527, 0.125, 0.2441, 0.4219, 0.6699, 1, 1),
    tolerance = 0.1
  )
  expect_snapshot(d_max(x, 0, -1), error = TRUE)
  expect_snapshot(d_max(x, 0:1, 2), error = TRUE)
  expect_snapshot(d_max(x, 0, 1:2), error = TRUE)
  expect_snapshot(d_max(x, NA_real_, 1:2), error = TRUE)
  expect_snapshot(d_max(x, 0, NA_real_), error = TRUE)
  expect_snapshot(d_max(x, 0, 1, scale = -1), error = TRUE)
  expect_snapshot(d_max(x, 0, 1, scale = 1:2), error = TRUE)
  expect_snapshot(d_max(x, 0, 1, scale = NA), error = TRUE)

  # ------------------------------------------------------------------------------

  expect_equal(
    d_min(x, .1, .9),
    c(1, 1, 0.875, 0.75, 0.625, 0.5, 0.375, 0.25, 0.125, 0, 0)
  )
  expect_equal(
    d_min(x, 0, 1),
    c(1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0)
  )
  expect_equal(
    d_min(x, .1, .9, 1/2),
    c(1, 1, 0.9354, 0.866, 0.7906, 0.7071, 0.6124, 0.5, 0.3536, 0, 0),
    tolerance = 0.1
  )
  expect_equal(
    d_min(x, .1, .9, 3),
    c(1, 1, 0.6699, 0.4219, 0.2441, 0.125, 0.0527, 0.0156, 0.002, 0, 0),
    tolerance = 0.1
  )
  expect_snapshot(d_min(x, 0, -1), error = TRUE)
  expect_snapshot(d_min(x, 0:1, 2), error = TRUE)
  expect_snapshot(d_min(x, 0, 1:2), error = TRUE)
  expect_snapshot(d_min(x, NA_real_, 1:2), error = TRUE)
  expect_snapshot(d_min(x, 0, NA_real_), error = TRUE)
  expect_snapshot(d_min(x, .1, .9, scale = -1), error = TRUE)
  expect_snapshot(d_min(x, .1, .9, scale = 1:2), error = TRUE)
  expect_snapshot(d_min(x, .1, .9, scale = NA), error = TRUE)

  # ------------------------------------------------------------------------------

  expect_equal(
    d_target(x, .1, .3, .9),
    c(0, 0, 0.5, 1, 0.8333, 0.6667, 0.5, 0.3333, 0.1667, 0, 0),
    tolerance = 0.1
  )
  expect_equal(
    d_target(x, .1, .3, .9, 1/2, 3),
    c(0, 0, 0.7071, 1, 0.5787, 0.2963, 0.125, 0.037, 0.0046, 0, 0),
    tolerance = 0.1
  )
  expect_snapshot(d_target(x, 0:1, 2, 3), error = TRUE)
  expect_snapshot(d_target(x, 0, 1:2, 3), error = TRUE)
  expect_snapshot(d_target(x, 0, 1, 2:3), error = TRUE)
  expect_snapshot(d_target(x, NA_real_, 1, 2), error = TRUE)
  expect_snapshot(d_target(x, 0, NA_real_, 1), error = TRUE)
  expect_snapshot(d_target(x, 0, 1, NA_real_), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_low = -1), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_low = 1:2), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_low = NA), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_high = -1), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_high = 1:2), error = TRUE)
  expect_snapshot(d_target(x, .1, .3, .9, scale_high = NA), error = TRUE)

  # ------------------------------------------------------------------------------

  x_points <- (1:5)/5
  d_points <- c(0.36, 0.64, 0.84, 0.96, 1)
  expect_equal(
    d_custom(x, x_points, d_points),
    c(0, 0, 0.36, 0.5, 0.64, 0.74, 0.84, 0.9, 0.96, 0.98, 1),
    tolerance = 0.1
  )
  expect_snapshot(d_custom(x, x_points[-1], d_points), error = TRUE)
  expect_snapshot(d_custom(x, x_points, d_points[-1]), error = TRUE)
  expect_snapshot(d_custom(x, letters, d_points), error = TRUE)
  expect_snapshot(d_custom(x, x_points, letters), error = TRUE)

  # ------------------------------------------------------------------------------

  expect_equal(
    d_box(x, 0.2, .7),
    c(0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0),
    tolerance = 0.1
  )
  expect_snapshot(d_box(x, 0, -1), error = TRUE)
  expect_snapshot(d_box(x, 0:1, 2), error = TRUE)
  expect_snapshot(d_box(x, 0, 1:2), error = TRUE)
  expect_snapshot(d_box(x, NA_real_, 1:2), error = TRUE)
  expect_snapshot(d_box(x, 0, NA_real_), error = TRUE)

  # ------------------------------------------------------------------------------

  lvls <- (1:5)/5
  names(lvls) <- month.abb[2:6]
  expect_equal(
    d_category(month.abb[2:4], lvls),
    c(0.2, 0.4, 0.6)
  )

  oob <- lvls
  oob[1] <- 10
  expect_snapshot(d_category(month.abb[2:4], oob), error = TRUE)

  # ------------------------------------------------------------------------------

  expect_snapshot(d_min(letters, 1, 2), error = TRUE)
  expect_snapshot(d_min(letters[1], 1, 2), error = TRUE)

})

test_that('missing values', {
  expect_equal(d_max(NA_real_, 1, 2, missing = NA_real_), NA_real_)
  expect_equal(d_max(NA_real_, 1, 2, missing = .1), .1)

  expect_equal(d_min(NA_real_, 1, 2, missing = NA_real_), NA_real_)
  expect_equal(d_min(NA_real_, 1, 2, missing = .1), .1)

})