test_that("find_medoids() works", {
  D <- stats::dist(iris[, 1:4])
  expect_error(find_medoids(as.matrix(D)))
  out1 <- find_medoids(D)
  expect_equal(out1, 62L)
  memberships <- rep(1:3, each = 50L)
  expect_error(find_medoids(D, memberships))
  memberships <- as.factor(memberships)
  out2 <- find_medoids(D, memberships)
  expected <- c(8L, 97L, 113L)
  names(expected) <- c("1", "2", "3")
  expect_equal(out2, expected)
})