test_that("batch_names works", {
  index <- create_subset(100, 50, 2)
  batch <- batch_names(index)
  expect_length(unique(batch), 2)
  expect_true(all(batch[index[[1]]] == names(index)[1]))
  expect_true(all(batch[index[[2]]] == names(index)[2]))
})

test_that("batch_names and use_index are the opposite" ,{
  plates <- c("P1", "P2", "P1", "P2", "P2", "P3", "P1", "P3", "P1", "P1")
  expect_equal(batch_names(use_index(plates)), plates)
})

test_that("batch_names works with repeated samples", {
  index <- create_subset(100, 50, 2)
  index[[1]] <- c(index[[1]], index[[2]][1:5])
  index[[2]] <- c(index[[2]], index[[1]][1:5])

  expect_warning(bn <- batch_names(index))
  expect_gt(length(bn), max(unlist(index)))
})