test_that("Some affine transformation settings", {
  skip_if_not(getRversion() >= "4.2.0")
  skip_on_cran()
  # upper right pyramid face
  df <- data.frame(x = c(5.66061867341471, 4.96693859488835, 4.51615802188193, 5.20983810040828),
                   y = c(5.20983810040828, 4.51615802188193, 4.96693859488835, 5.66061867341471))
  vpi <- affine_settings(df)
  expect_true(vpi$flipX)
  expect_equal(vpi$angle, -45)

  # left pyramid face
  df <- data.frame(x = c(0.548321978113589, 1.63846635232886, 1.63179192889832, 0.541647554683048),
                       y = c(3.20646280984155, 3.67766227203477, 3.44151334764832, 2.97031388545509))
  vpi <- affine_settings(df)
  expect_true(vpi$flipX)
  expect_equal(vpi$angle, 88.381045)

  # lower-left pyramid left
  df <- data.frame(x = c(0.993133639601288, 1.58950508250181, 1.23595169190854, 0.639580249008014),
                       y = c(0.639580249008014, 1.23595169190854, 1.58950508250181, 0.993133639601288))
  vpi <- affine_settings(df)
  expect_false(vpi$flipX)
  expect_equal(vpi$angle, 135)

  # bottom pyramid back
  df <- data.frame(x = c(2.99330183384669, 3.37276334764832, 3.56293637525157, 3.18347486144994),
                       y = c(0.64809266481788, 1.52599654139832, 1.5313715195592, 0.653467642978757))
  vpi <- affine_settings(df)
  expect_true(vpi$flipX)
  expect_equal(vpi$angle, -178.381045)

  # lower-left pyramid back
  df <- data.frame(x = c(0.842511262411246, 1.23595169190854, 1.18364305569535, 0.790202626198057),
                   y = c(0.842511262411246, 1.58950508250181, 1.53719644628862, 0.790202626198057))
  vpi <- affine_settings(df)
  expect_false(vpi$flipX)
  expect_equal(vpi$angle, -135)
})