# test_that("duplication matrix n = 2", {
#   D <- duplication_mat(2)
#
#   m <- matrix(c(1, 0, 0,
#                 0, 1, 0,
#                 0, 1, 0,
#                 0, 0, 1), ncol = 3, byrow = TRUE)
#
#   expect_equal(D, m)
# })
#
# test_that("duplication matrix n = 3", {
#   D <- duplication_mat(3)
#
#   m <- matrix(c(1, 0, 0, 0, 0, 0,
#                 0, 1, 0, 0, 0, 0,
#                 0, 0, 1, 0, 0, 0,
#                 0, 1, 0, 0, 0, 0,
#                 0, 0, 0, 1, 0, 0,
#                 0, 0, 0, 0, 1, 0,
#                 0, 0, 1, 0, 0, 0,
#                 0, 0, 0, 0, 1, 0,
#                 0, 0, 0, 0, 0, 1), ncol = 6, byrow = TRUE)
#
#   expect_equal(D, m)
# })