test_that("categorize() works", {
  set.seed(123)
  M <- as.data.frame(mvtnorm::rmvnorm(20, mean = rep(0, 3), sigma = 2 * diag(3)))

  C <- categorize(M, labels = letters[1:3])
  expect_s3_class(C, "data.frame")
  expect_equal(dim(C), c(20, 3))

  C <- categorize(M)
  expect_s3_class(C, "data.frame")
  expect_equal(dim(C), c(20, 3))
})