test_that("OptimizerBatchChain", {
  z = test_optimizer_1d("chain", term_evals = 20L,
    optimizers = list(opt("random_search"), opt("grid_search")),
    terminators = list(trm("evals", n_evals = 10L), trm("evals", n_evals = 10L)))
  expect_class(z$optimizer, "OptimizerBatchChain")
  expect_output(print(z$optimizer), "OptimizerBatchChain")
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchRandomSearch_1"]$batch_nr, 1:10)
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchGridSearch_1"]$batch_nr, 11:20)

  z = test_optimizer_2d("chain", term_evals = 20L,
    optimizers = list(opt("random_search"), opt("grid_search")),
    terminators = list(trm("evals", n_evals = 10L), trm("evals", n_evals = 10L)))
  expect_class(z$optimizer, "OptimizerBatchChain")
  expect_output(print(z$optimizer), "OptimizerBatchChain")
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchRandomSearch_1"]$batch_nr, 1:10)
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchGridSearch_1"]$batch_nr, 11:20)

  z = test_optimizer_2d("chain", term_evals = 20L,
    optimizers = list(opt("random_search", batch_size = 10L), opt("grid_search", batch_size = 10L)),
    terminators = list(trm("evals", n_evals = 10L), trm("evals", n_evals = 10L)))
  expect_class(z$optimizer, "OptimizerBatchChain")
  expect_output(print(z$optimizer), "OptimizerBatchChain")
  expect_identical(unique(z$instance$archive$data[.optimizer_id == "OptimizerBatchRandomSearch_1"]$batch_nr), 1L)
  expect_identical(unique(z$instance$archive$data[.optimizer_id == "OptimizerBatchGridSearch_1"]$batch_nr), 2L)

  z = test_optimizer_dependencies("chain", term_evals = 20L,
    optimizers = list(opt("random_search"), opt("grid_search")),
    terminators = list(trm("evals", n_evals = 10L), trm("evals", n_evals = 10L)))
  expect_class(z$optimizer, "OptimizerBatchChain")
  expect_output(print(z$optimizer), "OptimizerBatchChain")
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchRandomSearch_1"]$batch_nr, 1:10)
  expect_identical(z$instance$archive$data[.optimizer_id == "OptimizerBatchGridSearch_1"]$batch_nr, 11:20)

  # random restarts
  terminator = trm("none")
  instance = OptimInstanceBatchSingleCrit$new(
    objective = OBJ_1D,
    search_space = PS_1D,
    terminator = terminator
  )
  skip_if_not_installed("GenSA")
  z = test_optimizer(
    instance = instance,
    key = "chain",
    optimizers = list(opt("gensa"), opt("gensa")),
    terminators = list(trm("evals", n_evals = 10L), trm("evals", n_evals = 10L)),
    real_evals = 20L
  )
  expect_identical(unique(z$instance$archive$data$.optimizer_id), c("OptimizerBatchGenSA_1", "OptimizerBatchGenSA_2"))

  # packages, properties, param_set, etc.
  optimizer = OptimizerBatchChain$new(optimizers = list(opt("random_search"), opt("gensa")))
  expect_set_equal(optimizer$packages, c("bbotk", "GenSA"))
  expect_identical(optimizer$properties, "single-crit")
  expect_identical(optimizer$param_classes, "ParamDbl")
  expect_set_equal(
    optimizer$param_set$ids(),
    c("OptimizerBatchRandomSearch_1.batch_size", "OptimizerBatchGenSA_1.smooth", "OptimizerBatchGenSA_1.temperature",
      "OptimizerBatchGenSA_1.visiting.param", "OptimizerBatchGenSA_1.acceptance.param", "OptimizerBatchGenSA_1.simple.function",
      "OptimizerBatchGenSA_1.verbose", "OptimizerBatchGenSA_1.trace.mat")
  )
})